In a jar there are balls in different colors: blue, red, green and yellow.

In a jar there are balls in different colors: blue, red, green and yellow. The probability of drawing a blue ball is 1/8. The probability of drawing a red ball is 1/5. The probability of drawing a green ball is 1/7. If a jar cannot contain more than 500 balls, how many yellow balls are in the Jar?

Quiz

Answer/Solution

149.

Steps/Work

We need to get some number which is less than 500 and exactly divisible by 8,5 and 7
Lets take LCM of three balls 8,5 and 7 = 280.
The probability of drawing a blue ball is 1/8...For every 8 balls we get 1 BLUE ball then out of 280 balls we get 35 BLUE balls.
The probability of drawing a red ball is 1/5...For every 5 balls we get 1 RED ball then out of 280 balls we get 56 REB balls.
The probability of drawing a green ball is 1/7. For every 7 balls we get 1 GREEN ball then out of 280 balls we get 40 GREEN BALLS.
Then out of 280 - ( 35 + 56 + 40 ) = 149 YELLOW balls.
IMO option E is correct.