SOLUTION: a box contains 25 balls numbered from 1 to 25.one ball is drawn at random.what is the probability tha the number of the drawn ball will be a multiple of 3 or 5?

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Question 761914: a box contains 25 balls numbered from 1 to 25.one ball is drawn at random.what is the probability tha the number of the drawn ball will be a multiple of 3 or 5?
Answer by ramkikk66(644) (Show Source):
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Total number of possible outcomes = 25
No. of favourable outcomes to get a multiple of 3 = 8 (because there are 8 multiples of 3 between 1 and 25)
No. of favourable outcomes to get a multiple of 5 = 5(because there are 5 multiples of 5 between 1 and 25)
So no. of outcomes of getting multiples of 3 or 5 = 8 + 5 = 13.
But here's the catch - there is one number 15 which is both a multiple of 3 and 5 and would get counted twice in both the above sets. We need to subtract that.
Hence, no of possibilities of getting a multiple of 3 or 5 = no. of possibilities of getting multiple of 3 + no. of possibilities of getting 5 - no. of possibilities of getting 15 = = 12.
The probability of getting a multiple of 3 or 5 = (12/25) or 48%.

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