A bag contains balls numbered from 1 to 42. One ball is drawn at random from these balls. The probability that its number is a multiple of 7 or 8 is:
11⁄42
Numbers from 1 to 42 that are multiples of 7: {7, 14, 21, 28, 35, 42} → 6 numbers Numbers that are multiples of 8: {8, 16, 24, 32, 40} → 5 numbers Numbers that are multiples of both 7 and 8 (LCM = 56, but 56 is not in range) → 0 numbers Using the formula for union in probability: P(A ∪ B) = P(A) + P(B) - P(A ∩ B) = (6/42) + (5/42) - (0/42) = 11/42
Important Questions from Probability
Two dice are thrown simultaneously. What is the probability of getting the same number on both the dice?
The probability of being 53 Sundays in year 2020 is-
Three dice are thrown randomly. The probability of coming 3 in at least one die is
The probability of having 53 Tuesdays in an ordinary year is:
When two dice are tossed simultaneously, the probability that the sum of the numbers appearing on both the dice is 8 will be
