Question 1174116

One morning, Justin drove 3 hours before stopping to eat lunch at Chick-fil-A. After lunch, he increased his speed by 10 mph. If he completed a 450-mile trip in 8 hours of driving time, how fast did he drive in the morning?
<pre>Let speed in the morning be S
Then speed after lunch = S + 10
We then get the following DISTANCE equation: 3S + 5(S + 10) = 450
3S + 5S + 50 = 450
8S = 400
Speed in the morning or {{{highlight_green(matrix(1,6, S, "=", 400/8, "=", 50, mph))}}}