On Her Way to a Holiday Weekend, Nancy Drove $2 \frac{1}{2}$

Multiple Choice

On her way to a holiday weekend, Nancy drove $2 \frac{1}{2}$ hours in rush- hour traffic. When traffic eased up, she was able to increase her speed by 42 miles per hour and drove another $4 \frac{1}{2}$ hours. If the entire trip was 371 miles, how fast did she drive in rush- hour traffic?

A) $26 \mathrm{mph}$
B) $28 \mathrm{mph}$
C) $27 \frac{1}{2} \mathrm{mph}$
D) $27 \mathrm{mph}$