Class A is twice as big as Class B. Class A is also a third the size of Class C. If Class B has 20 people in it, how many people are in Class C?
Let’s work this out in a step by step way to be sure we have the right answer.
120
Class A is twice the size of Class B, so Class A = 2 * size of Class B.

If Class B has 20 people Class A has 20 * 2 = 40 people.

Since Class A is also 1 / 3 the size of Class C then Class A = 1 / 3 * Class C.

This means 40 = 1 / 3 * Class C.

Thus the size of Class C is 3 * 40 = 120 people.

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The answer is 120