Question

A bag contains 40 red and green marbles. The number of green marbles, g, is 9 times the number of red marbles, r.

How many red marbles are in the bag?

Answer 1

4 red marbles

Explanation:

green marbles = 9r

red marbles = r

9r + r = 40

10r = 40

r = 4 = red marbles