Quiz Discussion

There are 20 people among whom two are sisters. Find the number of ways in which we can arrange them around a circle so that there is exactly one person between the two sisters.

• 1]

  2! x 19!

• 2]

  18!

• 3]

  18! x 2!

• 4]

  19!

If P(A)=2/5​, P(B)=3/10​ and P(A ∩ B) =51​, then P(A' | B'). P(B' | A') is equal to

• 1]

  5/6

• 2]

  5/7

• 3]

  25/42

• 4]

  1

A fair coin is tossed 5 times. What is the probability of getting at least three heads on consecutive tosses?

• 1]

  3/16

• 2]

  1/4

• 3]

  7/24

• 4]

  5/16

In how many ways can a group of 5 men and 2 women be made out of a total of 7 men and 3 women?

• 1]

  63

• 2]

  90

• 3]

  126

• 4]

  45

A number lock on a suitcase has 3 wheels each labeled with 10 digits from 0 to 9. If the opening of the lock is a particular sequence of three digits with no repeats, how many such sequences will be possible?

• 1]

  720

• 2]

  760

• 3]

  780

• 4]

  680

If A, B and C are mutually exclusive and exhaustive events of a random experiment such that P(B)=3/2​P(A) and P(C)=1/2​P(B), then P(A∪C)=

• 1]

  3/13

• 2]

  6/13

• 3]

  7/13

• 4]

  10/13

A, B, C, D and E sit on five chairs all of which are facing north. C will sit only on the leftmost chair and B will not sit anywhere to the left of A. In how many ways they can be seated?

• 1]

  10

• 2]

  18

• 3]

  36

• 4]

  12

What is the probability of getting at least one six in a single throw of three unbiased dice?s

• 1]

  91/216

• 2]

  1/216

• 3]

  200/216

• 4]

  17/216

In a group of 6 boys and 4 girls, four children are to be selected. In how many different ways can they be selected such that at least one boy should be there?

• 1]

  159

• 2]

  194

• 3]

  205

• 4]

  209

A person tosses an unbiased coin. When head turns up, he gets Rs.8 and tail turns up he loses Rs.4. If 3 coins are tossed, what is probability that he gets a profit of Rs.12?

• 1]

  3/8

• 2]

  5/8

• 3]

  3/4

• 4]

  1/8