Question

A bag contains 40 red and green marbles. The ratio of red marbles to

green marbles is 3 to 1. How many green marbles are in the bag?
A. 10
B. 15
C. 20
D. 30

Answer 1

The answer is A or 10

Answer 2

39/40

Explanation:

Since 39 out of 40 marbles are green, the probability of randomly choosing green is 39/40.

However, the probability becomes 100% when you look into the bag and choose a green marble. (Unless you are blind or unable to distinguish blue from green, in which case the probability remains 39/40.)