Probability of Combined Events

Question

A bag contains 22 red marbles, 15 purple marbles and a number of green marbles. A marble is randomly selected from the bag. Probability choosing red marble is 11/25. Find the number of green marbles in the bag.

Answer 1

Total number of marbles in the bag is 22 + 15+ number of green marbles

The probability of red is 22/t =11/25. so t=50.

Total number in bag- ( number of red + number of purple) = green

50 - (22+ 15) = = green

50-37

17 =green

Answer 2

well if g is the number (22 / [15 + 22 + g]) - 11/25

550 = 407 + 11g

143 = 11 g

g = 143 / 11 = 13

Answer 3

The simplest way to solve this is to note that, if there are 22 red balls and the probability of red balls is 11%,

22/number of balls = 11/100

11 (number of balls) = 2200

number of balls = 200

200 = red + purple + green = 22 + 15+ green

green = 200 - 15 -22 = 163