Question

John drove 5 hours before stopping to get gas. After he filled the tank, he increased his speed by 10 MPH. If he completed a 490-mile trip in 9 hours of driving time, how fast did he drive before he stopped for gas?

Answer 1

since time = distance/speed, then If his pre-gas speed was x mph, then

5 + (490-5x)/(x+10) = 9