# 15 Hardest Brain Teaser Questions And Answer Which Asked In Test

**Q1- What is the average speed of a car travelling 20 mph one way and returning the same distance at 60 mph the other way in miles per hour? **

A- 30

B- 50

C- 60

**Correct Answer Is A**

**Explanation: **Because the average rate does not equal the average of the rates, and because the answer is not 40, Furthermore, it is not necessary to know the distance between two points. It is possible to demonstrate that the average rate is 2ab/(a + b) in the case of two rates of a and b, i.e. 2(20)(60)/(20 + 60) = 30.

**Q2- Consider the following scenario: I have 40 blue socks and 40 brown socks in a drawer. If I reach into the drawer without looking at the socks, how many socks do I need to take out in order to ensure that I have a pair of socks that are the same color as the other? **

A- 2

B- 3

C- 4

**Correct Answer Is B**

**Explanation: **Start with two socks and work your way up to four socks for this problem. If you only get two pairs of socks, they may be of different colours, but getting three pairs ensures that you will have a pair of each colour. The strategy is to recognise that, in order to be certain of what you will receive, you must take into account the worst-case situation. The worst case scenario is that the first two times you reach into the drawer, you'll get two different colours of socks—say let's a blue sock and a brown sock on each of the first two occasions. In order to complete the third attempt, you must obtain either a blue or a brown sock, which will form a pair with one of the first two socks.

**Q3- What is the next number in the following sequence?**

0 0 1 2 2 4 3 6 4 8 5?

A- 6

B- 8

C- 10

**Correct Answer Is C
Explanation: **10 there are two alternating sequences: 0, 1, 2, 3, 4, 5 and 0, 2, 4, 6, 8.

**Q4- Consider the following scenario: you have a 12-hour digital clock with the number representing the hour on the face of the clock always being the same as the number representing the minute. To put it another way, the clock can only display times such as 8:08, 9:09, 10:10, and so on and so forth. In situations where two such times are separated by the smallest possible amount of time. **

A - 49 minutes

B - 61 minutes

C - 60 minutes

**Correct Answer is A
Explanation: **In order to get 61 minutes, it's tempting to simply subtract the times 9:09 from 10:10 and so on. However, this will result in 101 minutes if you're not careful. However, this is not the most effective strategy. When you compare the times that are the closest to one another, such as 12:12 and 1:01, you will find that the difference is 49 minutes between the two.

**Q5- The letters ABCD are formed by inscribing an ABCD square into a quarter-circle with B on the circumference of the circle and D in the centre of the circle, forming an ABCD square.**

**What is the length of the diagonal AC of the square if the circle's radius is five times the length of the square's diagonal AC? **

A - 3

B - 4

C - 5

**Correct Answer Is C**
**Explanation: **Drawing lines to demonstrate that BD is the radius of a circular figure is step 5 of 5. As a result, the two diagonals of a square will have lengths that are equal to one another.

**Q6- Bonnie's father is the father of five daughters, but he is the father of no sons. Four of the daughters have been given the names Chacha, Cheche, Chichi, and Chocho, respectively.**

**What is the fifth daughter’s name?**

(a) Chuchu

(b) Chochu

(c) Chuchy

**Explanation: **If the four daughters are those mentioned, think of who the fifth daughter could be—the fifth daughter is Bonnie herself

**Q7- Put these statements in the right order:**

(a) The ship stopped to anchor in Commander Bay.

(b) A boy awoke and saw a sea lion.

(c) A boy went ashore and napped in a meadow.

(d) A boy did not tell what he had seen.

(e) A boy got a job on a ship.

**Correct Order is e, a, c, b, d**

**Q8- By offering a sweater for 30% off, followed by a 10% off discount, one clothing store is able to compete with its competitors. The following is an example of the equivalent single discount: **

A - 34 percent

B - 36 percent

C- 37 percent

**Correct Answer is C
Explanation: **The single discount that is equal to the sum of the discounts is less than the total amount of the discounts taken together. Start with $100 and work your way up. The price drops to $70 after a 30 percent discount is applied. If you take a 10 percent discount off of a $70 purchase, you can get it for $63 instead. A $37 discount is obtained by dividing $100 by 63, which is the same as receiving a 37 percent discount on the same amount of money.

**Q9- Take 1,000. Add 40. Add another 1,000. Add 30. Add 1,000 again. Add 20. Add 1,000. And add 10. What is the total?**

A- 5,000

B- 4,100

C- 4,900

**Correct Answer is B
Explanation: **4,100 1,000 + 40 + 1,000 + 30 + 1,000 + 20 + 1,000 + 10 = 4,100.

**Q10- How many different committees can be formed from a pool of three people, where a committee can consist of one to three people?**

A-3

B- 4

C- 7

**Correct Answer is C**

**Q11- How many hours will it take four people to wash 100 cars if everyone at the car wash works at the same speed and eight people are able to wash 50 cars in 60 hours?**

A- 60

B- 120

C- 240

**Correct Answer is C**
**Explanation: **Make a list of the steps you'll take: If eight people can wash fifty cars in sixty hours, then four people can wash fifty cars in one hundred and twenty hours. Because there are half as many people to wash as there are people to wash, it would take twice as long to wash everyone. Due to the fact that there are twice as many cars now as there were previously, it would take four people 240 hours, or twice as long, to wash 100 vehicles.

**Q12- I toss a five-cent coin into the air, followed by a ten-cent coin. What is the likelihood that the five-cent coin will land on its head if one of them lands on its head? **

A- 1/3

B- 1/2

C- 2/3

**Correct Answer Is C**

**Explanation: **Probability can be defined as the proportion of favourable outcomes to the total number of possible outcomes divided by the number of favourable outcomes.

Assuming that one of the coins lands on its head, the following are the total number of ways this could happen:

five-cents for the head, ten-cents for the tail head for five cents, head for ten cents A five-cent tail and a ten-cent head are acceptable. Because we are told that one of the coins must be a head, there is no way that a ten-cent tail and ten-cent tail combination could be possible.

As a result, there are three possible outcomes. The following are the most likely scenarios in which the five-cent coin will land on its head:

five-cents for the head, ten-cents for the tail

head for five cents, head for ten cents

Out of three possible outcomes, this is two of them. As a result, there is a 2/3 chance of success.

**Q13- There is 3 dimes, 3 nickels and 3 quarters, how many ways can I make change for $1.00?**

A- 1

B- 2

C- 3

**Correct Answer Is B**
**Explanation: **2 5n + 10d + 25q = 100, where n is the number of nickels, d is the number of dimes, and q is the number of quarters. Begin with the smallest n, d, and q values that satisfy the equation. Begin with n = 0, d = 0, and q = 4, which is not correct because the maximum q possible is 3. Then experiment with n = 0 and d = 1. The result is 25q = 90, which does not yield a whole number for q. You will find that the equation is satisfied if n = 1, d = 2, and q = 3, and if n = 3, d = 1, and q = 3. So there are two options for effecting change.

**Q14- Which of the following fractions is smallest?**

A- 11/20

B- 5/6

C- 5/7

**Correct Answer is A- 11/20**

**Q15- 50 × 50 × 50 x(where there are a hundred 50s) is how many times 100 × 100 × 100 x(where there are fifty 100s)?**

A- 25 × 25 × 25 ×…(where there are fifty 25s)

B- 4 × 4 × 4 ×…(where there are fifty 4s)

C- 2 × 2 × 2 ×…(where there are fifty 2s)

**Correct Answer is A
Explanation: **25 × 25 × 25 ×…(where there are fifty 25s) Try to find a connection between the numbers. You are comparing 50 × 50 × 50 × 50…(100 times) to 100 × 100 × 100 × 100… (50 times). Write 100 as 50 × 2, so now you are comparing 50 × 50 × 50 × 50…(100 times) to 50 × 2 × 50 × 2 × 50 × 2 × 50 × 2…(50 times).You can now cancel 50 × 50 × 50 × 50…50 times from both sides of the comparison. You would then get 50 × 50 × 50 × 50…(50 times) compared with 2 × 2 × 2 × 2…(50 times). You can see the left side of the comparison is 25 × 25 × 25 × 25…(50 times) times the right side.