Quiz Discussion

If ¹⁸C_r = ¹⁸C_r+2 ; find ^rC₅.

• 1]

  56

• 2]

  63

• 3]

  49

• 4]

  42

A box contains two white balls, three black balls and four red balls. Balls of the same colour are distinct. The number of ways in which three balls can be drawn from the box if atleast one black ball is to be included in the draw, is

• 1]

  32

• 2]

  64

• 3]

  128

• 4]

  None Of These

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 coin is tossed 5 times. What is the probability that head appears an odd number of times?

• 1]

  1/2

• 2]

  2/3

• 3]

  1/3

• 4]

  1

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

In how many different ways can the letters of the word 'DETAIL' be arranged in such a way that the vowels occupy only the odd positions?

• 1]

  32

• 2]

  48

• 3]

  36

• 4]

  60

How many words, with or without meaning, can be formed using all letters of the word EQUATION using each letter exactly once?

• 1]

  38,320

• 2]

  39,320

• 3]

  38,400

• 4]

  40,320

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

Four letters are selected from the word “CAPAME” and are rearranged to form four letter words. How many words can be formed?

• 1]

  120

• 2]

  90

• 3]

  180

• 4]

  192

Two variants of the CAT paper are to be given to 12 students. In how many ways can the students be placed in two rows of six each so that there should be no identical variants side by side and that the students sitting one behind the other should have the same variant. Find the number of ways this can be done

• 1]

  2 x ¹²C₆ x (6!)²

• 2]

  2 x 6! x 6!

• 3]

  2 x ¹²C₆ x 6!

• 4]

  None of these