Thinkster Math Recruitment Process, Interview Questions & Answers

Q: A man has a wolf, a goat, and a cabbage. He must cross a river with the two animals and the cabbage. There is a small rowing-boat, in which he can take only one thing with him at a time. If, however, the wolf and the goat are left alone, the wolf will eat the goat. If the goat and the cabbage are left alone, the goat will eat the cabbage. How can the man get across the river with the two animals and the cabbage?

Q: A hare and a tortoise have a race along a circle of 100 yards diameter. The tortoise goes in one directionand the hare in the other. The hare starts after the tortoise has covered 1/5 of its distance and that too leisurely.The hare and tortoise meet when the hare has covered only 1/8 of the distance. By what factor should the hareincrease its speed so as to tie the race?

Q: A rich merchant had collected many gold coins. He did not want anybody to know about them. One day his wife asked, "How many gold coins do we have?" After pausing a moment, he replied, "Well! If I divide the coins into two unequal numbers, then 32 times the difference between the two numbers equals the difference between the squares of the two numbers."The wife looked puzzled. Can you help the merchant's wife by finding out how many gold coins they have?

Q: Suppose a newly-born pair of rabbits, one male, one female, are put in a field. Rabbits are able to mate at the age of one month so that at the end of its second month a female can produce another pair of rabbits. Suppose that our rabbits never die and that the female always produces one new pair (one male, one female) every month from the second month on.

Q: 9 cards are there. You have to arrange them in a 3*3 matrix. Cards are of 4 colors. They are red, yellow, blue and green. Conditions for arrangement: one red card must be in first row or second row. 2 green cards should be in 3rd column. Yellow cards must be in the 3 corners only. Two blue cards must be in the 2nd row. At least one green card in each row.

Q: Consider a pile of Diamonds on a table. A thief enters and steals 1/2 of the total quantity and then again 2 extra from the remaining. After some time a second thief enters and steals 1/2 of the remaining+2. Then 3rd thief enters and steals 1/2 of the remaining+2. Then 4th thief enters and steals 1/2 of the remaining+2. When the 5th one enters he finds 1 diamond on the table. Find out the total no. of diamonds originally on the table before the 1st thief entered.

Q: 3 policemen and 3 thieves had to cross a river using a small boat. Only two can use the boat for a trip. All the 3 policemen and only 1 thief knew to ride the boat. If 2 thieves and 1 policeman were left behind they would kill him. But none of them escaped from the policemen. How would they be able to cross the river?

Q: 36 people {a1, a2, ..., a36} meet and shake hands in a circular fashion. In other words, there are totally 36 handshakes involving the pairs, {a1, a2}, {a2, a3}, ..., {a35, a36}, {a36, a1}. Then size of the smallest set of people such that the res...

Q: ABCDE are sisters. Each of them gives 4 gifts and each receives 4 gifts No two sisters give the same combination ( e.g. if A gives 4 gifts to B then no other sisters can give four to other one.) (i) B gives four to A.(ii) C gives 3 to E. How much did A,B,C,E give to D?

Q: At 6?o a clock ticks 6 times.The time between first and last ticks is 30 seconds.How long does it tick at 12?o clock?2.A hotel has 10 storey. Which floor is above the floor below the floor, below the floor above the floor, below the floor above the fifth.

Q: There is a room with a door (closed) and three light bulbs. Outside the room there are three switches, connected to the bulbs. You may manipulate the switches as you wish, but once you open the door you can't change them. Identify each switch with its bulb.

Q: The egg vendor calls on his first customer and sells half his eggs and half an egg. To the second customer, he sells half of what he had left and half an egg and to the third customer he sells half of what he had then left and half an egg. By the way he did not break any eggs. In the end three eggs were remaining . How many total eggs he was having ?

Q: Every day a cyclist meets a train at a particular crossing .The road is straight before the crossing and both are travelling in the same direction.Cyclist travels with a speed of 10 kmph.One day the cyclist come late by 25 minutes and meets the train 5 km before the crossing.What is the speed of the train?

Q: A vessel is full of liquid. From the vessel, 1/3rd of the liquid evaporates on the first day. On the second day 3/4th of the remaining liquid evaporates. What fraction of the volume is present at the end of the second day

Q: Jarius and Kylar are playing the game. If Jarius wins, then he wins twice as many games as Kylar. If Jarius loses, then Kylar wins as the same number of games that Jarius wins. How many do Jarius and Kylar play before this match?

Q: Raj has a jewel chest containing Rings, Pins and Ear-rings. The chest contains 26 pieces. Raj has 2 and 1/2 times as many rings as pins, and the number of pairs of earrings is 4 less than the number of rings. How many earrings does Raj have?...

Q: If I walk with 30 miles/hr i reach 1 hour before and if i walk with 20 miles/hr i reach 1 hour late. Find the distance between 2 points and the exact time of reaching destination is 11 am then find the speed with which it walks.

Q: Consider a series in which 8 teams are participating. each team plays twice with all other teams. 4 of them will go to the semi final. How many matches should a team win, so that it will ensure that it will go to semi finals.?

Q: An escalator is descending at constant speed. A walks down and takes 50 steps to reach the bottom. B runs down and takes 90 steps in the same time as A takes 10 steps. How many steps are visible when the escalator is not operating. 

Q: A family X went for a vacation. Unfortunately it rained for 13 days when they were there. But whenever it rained in the mornings, they had clear afternoons and vice versa. In all they enjoyed 11 mornings and 12 afternoons. How many days did they stay there totally?