A box contains 20 balls bearing numbers 1, 2, 3, 4 … 20. A ball is drawn at random from the box. What is the probability that the number on the ball is

(i) divisible by 2 or 3

(ii) not divisible by 10?

Asked by Topperlearning User | 27th Jul, 2017, 04:28: PM

Expert Answer:

Total number of outcomes = 20

(i) Numbers "divisible by 2" are 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, i.e., 10 in number.

Numbers "divisible by 3" are 3, 6, 9, 12, 15, 18, i.e., 6 in number.

Number "divisible by 2 and 3" are 6, 12, 18, i.e., 3 in number.

Number of favourable outcomes = 3

\\Required probability ==

 

(ii) Numbers divisible by 10 are 10, 20, i.e., 2 in number.

\\ Numbers which are not divisible by 10 = 20 - 2 = 18

\\ Required probability =

Answered by  | 27th Jul, 2017, 06:28: PM

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