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Math Interview Questions

Top Math interview questions

  1. If Log2 x - 5 Log x + 6 = 0, then what would the value / values of x be?
  2. A number of cats got together and decided to kill between them 999919 mice. Every cat killed an equal number of mice. Each cat killed more mice than there were cats. How many cats do you think there were ?
  3. Three cards are drawn at random from an ordinary pack of cards. Find the probability that they will consist of a king, a queen and an ace.
  4. The average age of 10 members of a committee is the same as it was 4 years ago, because an old member has been replaced by a young member. Find how much younger is the new member ?
  5. Mr. Shah decided to walk down the escalator of a tube station. He found that if he walks down 26 steps, he requires 30 seconds to reach the bottom. However, if he steps down 34 stairs he would only require 18 seconds to get to the bottom. If the time is measured fromthe moment the top step begins to descend to the time he steps off the last step at the bottom, find out the height of the stair way in steps?
  6. A boat travels 20 kms upstream in 6 hrs and 18 kms downstream in 4 hrs.Find the speed of the boat in still water and the speed of the water current?
  7. Pipe A can fill in 20 minutes and Pipe B in 30 mins and Pipe C can empty the same in 40mins. If all of them work together, find the time taken to fill the tank
  8. If x=y=2z and xyz=256 then what is the value of x?
  9. What is the angle between the two hands of a clock when time is 8:30
  10. If there are 1024*1280 pixels on a screen and each pixel can have around 16 million colors. Find the memory required for this?
  11. A boy has Rs 2. He wins or loses Re 1 at a time If he wins he gets Re 1 and if he loses the game he loses Re 1. He can loose only 5 times. He is out of the game if he earns Rs 5. Find the number of ways in which this is possible?
  12. How many 1’s are there in the binary form of 8*1024 + 3*64 + 3
  13. A man leaves office daily at 7pm A driver with car comes from his home to pick him from office and bring back homeOne day he gets free at 5:30 and instead of waiting for driver he starts walking towards home. In the way he meets the car and returns home on car He reaches home 20 minutes earlier than usual.In how much time does the man reach home usually??
  14. In objective test a correct ans score 4 marks and on a wrong ans 2 marks are subtracted, a student score 480 marks from 150 question. how many ans were correct?
  15. 5 men or 8 women do equal amount of work in a day. a job requires 3 men and 5 women to finish the job in 10 days how many woman are required to finish the job in 14 days.
  16. If an item costs Rs.3 in ‘99 and Rs.203 in ‘00.What is the % increase in price?
  17. A cylinder is 6 cms in diameter and 6 cms in height. If spheres of the same size are made from the material obtained, what is the diameter of each sphere?
  18. Two trains move in the same direction at 50 kmph and 32 kmph respectively. A man in the slower train observes the 15 seconds elapse before the faster train completely passes by him. What is the length of faster train ?
  19. If a sum of money compound annually amounts of thrice itself in 3 years. In how many years will it become 9 times itself
  20. A certain number of men can finish a piece of work in 10 days. If however there were 10 men less it will take 10 days more for the work to be finished. How many men were there originally?
  21. If on an item a company gives 25% discount, they earn 25% profit. If they now give 10% discount then what is the profit percentage.
  22. There are two circles, one circle is inscribed and another circle is circumscribed over a square. What is the ratio of area of inner to outer circle?
  23. City A’s population is 68000, decreasing at a rate of 80 people per year. City B having population 42000 is increasing at a rate of 120 people per year. In how many years both the cities will have same population?
  24. 20% of a 6 litre solution and 60% of 4 litre solution are mixed. What percentage of the mixture of solution
  25. Perimeter of the back wheel = 9 feet, front wheel = 7 feet on a certain distance, the front wheel gets 10 revolutions more than the back wheel. What is the distance?
  26. Each side of a rectangle is increased by 100% .By what percentage does the areaincrease?
  27. An equilateral triangle of sides 3 inch each is given. How many equilateral triangles of side 1 inch can be formed from it?
  28. A school has 30% students from Maharashtra .Out of these 20% are Bombey students. Find the total percentage of Bombay?
  29. If the total distance of a journey is 120 km .If one goes by 60 kmph and comes back at 40kmph what is the average speed during the journey?
  30. A worker is paid Rs.20/- for a full days work. He works 1,1/3,2/3,1/8.3/4 days in a week. What is the total amount paid for that worker ?
  31. To 15 lts of water containing 20% alcohol, we add 5 lts of pure water. What is % alcohol.
  32. The cost of an item is Rs 12.60. If the profit is 10% over selling price what is the selling price ?
  33. If PQRST is a parallelogram what it the ratio of triangle PQS & parallelogram PQRST
  34. There are two candles of equal lengths and of different thickness. The thicker one lasts of six hours. The thinner 2 hours less than the thicker one. Ramesh lights the two candles at the same time. When he went to bed he saw the thicker one is twice the length of the thinner one. How long ago did Ramesh light the two candles
  35. There is a square of side 6cm . A circle is inscribed inside the square. Find the ratio of the area of circle to square.
  36. The price of a product is reduced by 30% . By what percentage should it be increased to make it 100%
  37. 1/3 of girls , 1/2 of boys go to canteen .What factor and total number of classmates go to canteen.
  38. What is the selling price of a car? If the cost of the car is Rs.60 and a profit of 10% over selling price is earned
  39. Of Abdul, Binoy, and Chandini:a)Each member belongs to the Tee family whose members always tell the truth or to the El family whose members always lie.b)Abdul says ”Either I belong or Binoy belongs to a different family from the other two.”Whose family do you name of?
  40. Three piles of chips–pile I consists one chip, pile II consists of chips, and pile III consists of three chips–are to be used in game played by Anita and Brinda.The game requires:a)That each player in turn take only one chip or all chips from just one pile.b)That the player who has to take the last chip loses.c)That Anita now have her turn.From which pile should Anita draw in order to win?
  41. Mr. and Mrs. Aye and Mr. and Mrs. Bee competed in a chess tournament.Of the three games played:a)In only the first game werethe two players married to each other.b)The men won two games and the women won one game.c)The Ayes won more games than the Bees.d)Anyone who lost game did not play the subsequent game.Who did not lose a game?
  42. One of Mr. Horton,his wife,their son,and Mr. Horton’s mother is a doctor and another is a lawyer.a)If the doctor is younger than the lawyer, then the doctor and the lawyer are not blood relatives.b)If the doctor is a woman, then the doctor and the lawyer are blood relatives.c)If the lawyer is a man, then the doctor is a man.Whose occupation you know?
  43. One of Mr. Horton,his wife,their son,and Mr. Horton’s mother is a doctor and another is a lawyer.a)If the doctor is younger than the lawyer, then the doctor and the lawyer are not blood relatives.b)If the doctor is a woman, then the doctor and the lawyer are blood relatives.c)If the lawyer is a man, then the doctor is a man.Whose occupation you know?
  44. I drove 60 km at 30 kmph and then an additional 60 km at 50 kmph. Compute my average speed over my 120 km
  45. Divide 45 into four parts such that when 2 is added to the first part, 2 is subtracted from the second part, 2 is multiplied by the third part and the fourth part is divided by two, all result in the same number.
  46. How big will an angle of one and a half degree look through a glass that magnifies things three times?
  47. If time at this moment is 9 P.M., what will be the time 23999999992 hours later?
  48. Diophantus passed one sixth of his life in childhood, one twelfth in youth, and one seventh more as a bachelor; five years after his marriage a son was born who died four years before his father at half his final age. How old is Diophantus?
  49. With just six weights and a balance scale, you can weigh any unit number of kgs from 1 to 364. What could be the six weights?
  50. A cylindrical container has a radius of eight inches with a height of three inches. Compute how many inches should be added to either the radius or height to give the same increase involume?
  51. If s(a) denotes square root of a, find the value of s(12+s(12+s(12+ …… upto infinity.
  52. What is the sum of all numbers between 100 and 1000 which are divisible by 14 ?
  53. Three pipes, A, B, & C are attached to a tank. A & B can fill it in 20 & 30 minutesrespectively while C can empty it in 15 minutes. If A, B & C are kept open successively for 1 minute each, how soon will the tank be filled?
  54. A garrison of 3300 men has provisions for 32 days, when given at a rate of 850 grams per head. At the end of 7 days a reinforcement arrives and it was found that now the provisions will last 8 days less, when given at the rate of 825 grams per head. How, many more men can it feed?
  55. Solve for x and y: 1/x - 1/y = 1/3, 1/x2 + 1/y2 = 5/9.
  56. The minute hand of a clock overtakes the hour hand at intervals of 64 minutes of correct time. How much a day does the clock gain or lose?
  57. A man ate 100 bananas in five days, each day eating 6 more than the previous day. How many bananas did he eat on the first day?
  58. A wizard named Nepo says “I am only three times my son’s age. My father is 40 years more than twice my age. Together the three of us are a mere 1240 years old.” How old is Nepo?
  59. A certain type of mixture is prepared by mixing brand A at Rs.9 a kg. with brand B at Rs.4 a kg. If the mixture is worth Rs.7 a kg., how many kgs. of brand A are needed to make 40kgs. of the mixture?
  60. What is the missing number in this series? 8 2 14 6 11 ? 14 6 18 12
  61. Can you tender a one rupee note in such a manner that there shall be total 50 coins but none of them would be 2 paise coins.?
  62. The square of a two digit number is divided by half the number. After 36 is added to the quotient, this sum is then divided by 2. The digits of the resulting number are the same as those in the original number, but they are in reverse order. The ten’s place of the originalnumber is equal to twice the difference between its digits. What is the number?
  63. A rectangular plate with length 8 inches, breadth 11 inches and thickness 2 inches is available. What is the length of the circular rod with diameter 8 inches and equal to the volume of the rectangular plate?
  64. Out of 80 coins, one is counterfeit. What is the minimum number of weighings needed to find out the counterfeit coin?
  65. Gavaskar’s average in his first 50 innings was 50. After the 51st innings, his average was 51. How many runs did he score in his 51st innings. (supposing that he lost his wicket in his 51st innings)
  66. A fast typist can type some matter in 2 hours and a slow typist can type the same in 3 hours. If both type combinely, in how much time will they finish?
  67. What is the number of zeros at the end of the product of the numbers from 1 to 100?
  68. For the following, find the next term in the series1. 6, 24, 60,120, 210
  69. A man bought a horse and a cart. If he sold the horse at 10 % loss and the cart at 20 % gain, he would not lose anything; but if he sold the horse at 5% loss and the cart at 5% gain, he would lose Rs. 10 in the bargain. The amount paid by him was Rs.- _______ for the horse and Rs.________ for the cart.
  70. There are 3 persons Sudhir, Arvind, and Gauri. Sudhir lent cars to Arvind and Gauri as many as they had already. After some time Arvind gave as many cars to Sudhir and Gauri as many as they have. After sometime Gauri did the same thing. At the end of this transaction each one of them had 24. Find the cars each originally had.
  71. The number that does not have a reciprocal is ____________.
  72. Which of the following is larger than 3/5? (1) ? (2) 39/50 (3) 7/25 (4) 3/10 (5) 59/100
  73. The length of the side of a square is represented by x+2. The length of the side of an equilateral triangle is 2x. If the square and the equilateral triangle have equal perimeter, then the value of x is _______.
  74. If every alternative letter starting from B of the English alphabet is written in small letter, rest all are written in capital letters, how the month “September” be written. (1) SeptEMbEr (2) SEpTeMBEr (3) SeptembeR (4) SepteMber (5) None of the above.
  75. Which of the following statements drawn from the given statements are correct? Given: All watches sold in that shop are of high standard. Some of the HMT watches are sold in that shop. a) All watches of high standard were manufactured by HMT. b) Some of the HMT watches are of high standard. c) None of the HMT watches is of high standard. d) Some of the HMT watches of high standard are sold in that shop.
  76. All men are vertebrates. Some mammals are vertebrates. Which of the following conclusions drawn from the above statement is correct. 1. All men are mammals 2. All mammals are men 3. Some vertebrates are mammals. 4. None
  77. If point P is on line segment AB, then which of the following is always true? (1) AP = PB (2) AP > PB (3) PB > AP (4) AB > AP (5) AB > AP + PB
  78. If a light flashes every 6 seconds, how many times will it flash in ? of an hour?
  79. Five boys were climbing a hill. J was following H. R was just ahead of G. K was between G & H. They were climbing up in a column. Who was the second?
  80. Five farmers have 7, 9, 11, 13 & 14 apple trees, respectively in their orchards. Last year, each of them discovered that every tree in their own orchard bore exactly the same number of apples. Further, if the third farmer gives one apple to the first, and the fifth gives three to each of the second and the fourth, they would all have exactly the same number of apples. What were the yields per tree in the orchards of the third and fourth farmers?
  81. A tennis marker is trying to put together a team of four players for a tennis tournament out of seven available. males - a, b and c; females - m, n, o and p. All players are of equal ability and there must be at least two males in the team. For a team of four, all players must be able to play with each other under the following restrictions: b should not play with m, c should not play with p, and a should not play with o. Which of the following statements must be false? 1. b and p cannot be selected together 2. c and o cannot be selected together 3. c and n cannot be selected together.
  82. A man bought a horse and a cart. If he sold the horse at 10 % loss and the cart at 20 % gain, he would not lose anything; but if he sold the horse at 5% loss and the cart at 5% gain, he would lose Rs. 10 in the bargain. The amount paid by him was Rs.- _______ for the horse and Rs.________ for the cart.
  83. what is a percent of b divided by b percent of a?
  84. A contractor agreeing to finish a work in 150 days, employed 75 men each working 8 hours daily. After 90 days, only 2/7 of the work was completed. Increasing the number of men by ________ each working now for 10 hours daily, the work can be completed in time.
  85. A man was engaged on a job for 30 days on the condition that he would get a wage of Rs. 10 for the day he works, but he have to pay a fine of Rs. 2 for each day of his absence. If he gets Rs. 216 at the end, he was absent for work for … days.
  86. A software engineer has the capability of thinking 100 lines of code in five minutes and can type 100 lines of code in 10 minutes. He takes a break for five minutes after every ten minutes. How many lines of codes will he complete typing after an hour?
  87. A dishonest shopkeeper professes to sell pulses at the cost price, but he uses a false weight of 950gm. for a kg. His gain is____%.
  88. A student divided a number by 2/3 when he required to multiply by 3/2. Calculate the percentage of error in his result.
  89. It was calculated that 75 men could complete a piece of work in 20 days. When work was scheduled to commence, it was found necessary to send 25 men to another project. How much longer will it take to complete the work?