Quiz Discussion

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 value of  ⁷⁵P₂

• 1]

  5450

• 2]

  5555

• 3]

  5550

• 4]

  5656

A speaks truth in 75% cases and B in 80% of the cases. In what percentage of the cases are they likely to contradict each other, narrating the same incident?

• 1]

  5%

• 2]

  15%

• 3]

  35%

• 4]

  45%

Seven different objects must be divided among three people. In how many ways can this be done if one or two of them must get no objects?

• 1]

  36

• 2]

  84

• 3]

  180

• 4]

  381

Ten participants are participating in a competition. In how many ways can the first three prizes be won?

• 1]

  920

• 2]

  680

• 3]

  720

• 4]

  820

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

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

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

A, B, C, and D are four points, any three of which are non-collinear. Then, the number of ways to construct three lines each joining a pair of points so that the lines do not form a triangle is

• 1]

  7

• 2]

  8

• 3]

  9

• 4]

  24

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!