One morning, John drove 6 hours before stopping to eat.After lunch, he increased his speed by 10 mph. If he completed a 390-mile trip in 9 hours of driving time, how fast did he drive in the morning?
A) $\quad 33 \mathrm { mph }$
B) $\quad 36 \mathrm { mph }$
C) $\quad 48 \mathrm { mph }$
D) $\quad 43 \mathrm { mph }$
E) $\quad 40 \mathrm { mph }$

Question

Quizplus · Accepted Answer

John drove for 6 hours in the morning and 3 hours after lunch. Let $ x $ be his speed in the morning. Then his speed after lunch is $ x + 10 $. The equation is $ 6x + 3(x + 10) = 390 $. Solving gives $ x = 40 $ mph.

One Morning, John Drove 6 Hours Before Stopping to Eat 33mph\quad 33 \mathrm { mph }33mph

One Morning, John Drove 6 Hours Before Stopping to Eat $\quad 33 \mathrm { mph }$