Quiz Discussion

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

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!

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

12 person are seated at a round table. Number of ways of selecting 2 persons not adjacent to each other is

• 1]

  10

• 2]

  11

• 3]

  54

• 4]

  48

The students in a class are seated, according to their marks in the previous examination. Once, it so happens that four of the students got equal marks and therefore the same rank. To decide their seating arrangement, the teacher wants to write down all possible arrangements one in each of separate bits of paper in order to choose one of these by lots. How many bits of paper are required?

• 1]

  24

• 2]

  12

• 3]

  36

• 4]

  48

The number of triangles that can be formed by choosing the vertices from a set of 12 points, seven of which lie on the same straight line, is

• 1]

  185

• 2]

  175

• 3]

  115

• 4]

  105

From a group of 7 men and 6 women, five persons are to be selected to form a committee so that at least three men are in the committee. In how many ways can it be done?

• 1]

  624

• 2]

  702

• 3]

  756

• 4]

  812

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

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!) 

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!