Quiz Discussion

Three unbiased coins are tossed. What is the probability of getting at most two heads ?

• 1]

  3/4

• 2]

  1/4

• 3]

  3/8

• 4]

  7/8

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

Three chairs are arranged in a row facing three other chairs. 4 boys and 2 girls are to be seated on these chairs such that girls are always facing each other. In how many ways can they be seated?

• 1]

  96

• 2]

  72

• 3]

  144

• 4]

  120

How many numbers can be formed from 1, 2, 3, 4, 5 (without repetition), when the digit at the unit’s place must be greater than that in the ten’s place?

• 1]

  60

• 2]

  54

• 3]

  51 / 3

• 4]

  2 x 4!

There are 6 letters for 3 envelopes. In how many different ways can the envelopes be filled?

• 1]

  120

• 2]

  130

• 3]

  100

• 4]

  110

In a simultaneous throw of two dice, what is the probability of getting a total of 7?

• 1]

  1/6

• 2]

  1/4

• 3]

  2/3

• 4]

  3/4

There are 8 orators A, B, C, D, E, F, G, and H. In how many ways can the arrangements be made so that A always comes before B and B always comes before C.

• 1]

  8! / 3!

• 2]

  8! / 6!

• 3]

  5! x 3!

• 4]

  8! / (5! x 3!) 

From among the 36 students in a class, one leader and one class representative are to be appointed. In how many ways can this be done?

• 1]

  1360

• 2]

  1060

• 3]

  1160

• 4]

  1260

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 basketball team of 5 players is to be selected from a group of 10 men and 8 women players. A volley ball team of 6 players is to be selected from a group of 8 men and 7 women players. Find the difference in the number of ways in which both the teams are selected, given that each team has only 2 female players.

• 1]

  1890

• 2]

  1920

• 3]

  1950

• 4]

  1990