Quiz Discussion

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

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

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

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

A five-letter word is to be formed from a group of 5 vowels and 4 consonants, using at least one vowel and at least one consonant. In how many ways the word having a greater number of consonants than vowels can be formed?

• 1]

  40

• 2]

  42

• 3]

  45

• 4]

  52

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!

In how many different ways can the letters of the word 'OPTICAL' be arranged so that the vowels always come together?

• 1]

  120

• 2]

  720

• 3]

  4320

• 4]

  2160

If ,​, are probabilities of three mutually exclusive events, then

• 1]

  

• 2]

  

• 3]

  

• 4]

  None Of These

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

In a lottery, there are 10 prizes and 25 blanks. A lottery is drawn at random. What is the probability of getting a prize?

• 1]

  1/10

• 2]

  2/5

• 3]

  2/7

• 4]

  5/7