Problem #2248

2248.

Angelina drove at an average rate of $80$ km/h and then stopped $20$ minutes for gas. After the stop, she drove at an average rate of $100$ km/h. Altogether she drove $250$ km in a total trip time of $3$ hours including the stop. Which equation could be used to solve for the time $t$ in hours that she drove before her stop?


$\mathrm{(A)}\ 80t + 100(\frac{8}{3} -t) = 250 \qquad \mathrm{(B)}\ 80t = 250  \qquad \mathrm{(C)}\ 100t = 250$
$\mathrm{(D)}\ 90t = 250 \qquad \mathrm{(E)}\ 80(\frac{8}{3} -t) + 100t = 250$

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