Question

A bag contains 30 balls numbered from 1 to 30. One ball is drawn at random.

• A. The probability that the number of the drawn ball will be a multiple of 3 is 1/3
• B. The probability that the number of the drawn ball will be a multiple of 5 is 0.2
• C. The probability that the number of the drawn ball will be a multiple of 7 is 2/15
• D. The probability that the number of the drawn ball will be a multiple of 3 and 5 is 2/15

Answer 1

Answer: (A), (B), (C)

The correct options are
A The probability that the number of the drawn ball will be a multiple of 3 is 1/3
B The probability that the number of the drawn ball will be a multiple of 5 is 0.2
C The probability that the number of the drawn ball will be a multiple of 7 is 2/15

Total number $=$ 30
(A) Probability of the number being multiple of 3 is
P (3, 6, 9, 12, 15, 18, 21, 24, 27,30) $=\frac{10}{30}=\frac{1}{3}$
(B) Probability of the number being multiple of 5 is P(5, 10, 15, 20, 25, 30) $=\frac{6}{30}=\frac{1}{5}=0.2$
(C) Probability of the number being multiple of 7 is P (7,14, 21,28)$=\frac{4}{30}=\frac{1}{15}$
(D) Probability of the number being multiple of 3 and 5 is P(15,30) $=\frac{2}{30}=\frac{1}{15}$