Quiz Discussion

Three unbiased coins are tossed. What is the probability of getting at most two heads ?

• 1]

  3/4

• 2]

  1/4

• 3]

  3/8

• 4]

  7/8

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

A box contains 5 green, 4 yellow and 3 white marbles. three marbles are drawn at random. What is the probability that all they are not of the same colour?

• 1]

  3/44

• 2]

  3/55

• 3]

  52/55

• 4]

  41/44

What is the sum of all 4 digit numbers that can be formed by the digits 1, 2, 3, 4 each exactly once

• 1]

  55566

• 2]

  66660

• 3]

  56456

• 4]

  84738

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

How many rectangles can be formed out of a chess board ?

• 1]

  1740

• 2]

  1230

• 3]

  1296

• 4]

  204

How many natural numbers can be made with digits 0, 7, 8 which are greater than 0 and less than a million?

• 1]

  496

• 2]

  728

• 3]

  486

• 4]

  1084

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 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

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