Quiz Discussion

Six boys and 4 girls are to be seated in two separate rows with five chairs each, such that two particular girls are always together and all the girls are not in the same row. In how many ways can they be seated?

• 1]

  15 * 7!

• 2]

  20 * 8!

• 3]

  18 * 7!

• 4]

  (16 * 8! – 4! * 6!)

A number lock on a suitcase has 3 wheels each labeled with 10 digits from 0 to 9. If the opening of the lock is a particular sequence of three digits with no repeats, how many such sequences will be possible?

• 1]

  720

• 2]

  760

• 3]

  780

• 4]

  680

There are three rooms in a motel: one single, one double, and one for four persons. How many ways are there to house seven persons in these rooms?

• 1]

  7! / 1! 2! 3! 

• 2]

  7! 

• 3]

  7! / 3

• 4]

  7! / 3!

If ¹⁸C_r = ¹⁸C_r+2 ; find ^rC₅.

• 1]

  56

• 2]

  63

• 3]

  49

• 4]

  42

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

It is required to seat 5 boys and 4 girls in a row so that the girls occupy the even places. How many such arrangements are possible?

• 1]

  2880

• 2]

  2148

• 3]

  3280

• 4]

  3680

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

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

How many 4-letter words with or without meaning, can be formed out of the letters of the word, 'LOGARITHMS', if repetition of letters is not allowed?

• 1]

  40

• 2]

  400

• 3]

  5040

• 4]

  2520

A biased coin in tossed thrice. What is the probability that heads turns out at least twice considering that the probability of a head is 60%?

• 1]

  0.648

• 2]

  0.234

• 3]

  0.348

• 4]

  .839