Question

One morning, Justin drove 2 hours before stopping to eat lunch. After lunch, he increased his speed by 10 mph. If he completed a 220-mile trip in 6 hours of driving time, how fast (in miles per hour) did he drive in the morning

Answer 1

30

Explanation:

Let x be his speed at the morning, in miles per hour.

Then his speed after lunch was (x+10) mph.

2x + 3(x+10) = 220.

2x + 3x + 50 = 220