Question

A bag contain 5 red balls and some blue balls.If the probabloty of drawing a blue ball from the bag is thrice that of the red ball.Find the number of blue balls in the bag

Answer 1

3 x 5 = 15

Check:

If there is 15 blue balls then

Red ball probability: 5/20

Blue ball probability: 15/20

15/20 is thrice 5/20, so the answer is correct