50 balls are number 1 to 50 and a red dot is painted on those balls that are a multiple of 7. The balls are mixed into a bag and one ball is randomly chosen. What is the probability that the ball is numbered with a multiple of 5 or has a red dot?

Question

Landen Mathews

Mathematics

1 October, 08:35

50 balls are number 1 to 50 and a red dot is painted on those balls that are a multiple of 7. The balls are mixed into a bag and one ball is randomly chosen. What is the probability that the ball is numbered with a multiple of 5 or has a red dot?

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Answers (1)

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Areli Arellano · Answer 1

Hello,

The multiples of 7 are 7,14,21,28,35,42,49 : 7 balls

The multiples of 5 are 5,10,15,20,25,30,35,40,45,50 : 10 balls

In total there are 50 balls

But there is a commun ball 35

p = (7+10-1) / 50=16/50=8/25=0.32