#### Answer

The correct answer is (a).

#### Work Step by Step

Since the two coffees (say, $x$ and $y$) must add up to 100, we have $x+y=100$. Then, coffee $y$ would be $100-x$.

Published by
Pearson

ISBN 10:
0321979478

ISBN 13:
978-0-32197-947-6

The correct answer is (a).

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