2010 AMC 10B Problem 2

Question

Makayla attended two meetings during her

9

-hour work day. The first meeting took

45

minutes and the second meeting took twice as long. What percent of her work day was spent attending meetings?

15

20

25

30

35

Convert the meeting times to the same units

The meetings last

45+90

minutes out of

9

hours

Note that

45

minutes is

\dfrac{45}{60} = \dfrac{3}{4}

hours. The second meeting is then

2 \cdot \dfrac{3}{4} = \dfrac{3}{2}

hours. Both meetings take a total of

\dfrac{3}{4} + \dfrac{3}{2} = \dfrac{9}{4}

hours then. The percent of Makayla’s work day spent attending meetings is

100 \% \cdot \dfrac{\frac{9}{4}}{9} = 100 \% \cdot \dfrac{1}{4} = 25 \%.

Thus, C is the correct answer.

Problem 2 in other years