Question 180724
F = 10(x – 65) + 50 you are asked to find x for a given F
F = 10(x – 65) + 50 
{{{400 = 10(x - 65) + 50}}}
{{{400 = 10x - 650 + 50}}}
{{{400 = 10x - 600}}}
{{{1000 = 10x}}}
{{{100 = x}}}

The person was driving 100mph. One can only hope they were at the Michigan MotorSpeedway in a warm up lap.