Solve.
-Two automobiles going in opposite directions leave at the same time. One automobile travels $10 \mathrm { mph }$ faster than the other. In 8 hours the automobiles are 640 miles apart. Find the speed of each.
A) $15 \mathrm { mph } , 70 \mathrm { mph }$
B) $35 \mathrm { mph } , 45 \mathrm { mph }$
C) $25 \mathrm { mph } , 35 \mathrm { mph }$
D) $45 \mathrm { mph } , 55 \mathrm { mph }$

Question

Quizplus · Accepted Answer

Let the speed of the slower automobile be $x$ mph. Then, the speed of the faster automobile is $x + 10$ mph. Since they are moving in opposite directions, their relative speed is $x + (x + 10) = 2x + 10$ mph. In 8 hours, they cover $8(2x + 10) = 640$ miles. Solving $16x + 80 = 640$ gives $x = 35$ mph for the slower automobile and $x + 10 = 45$ mph for the faster automobile.

Solve -Two Automobiles Going in Opposite Directions Leave at the Same

Solve
-Two Automobiles Going in Opposite Directions Leave at the Same