Question

One morning, justin drove 2 hours before stopping to eat lunch at pizza hut. after lunch, he increased his speed by 10 mph. if he completed a 330-mile trip in 5 hours of driving time, how fast did he drive in the morning?

Answer 1

Speed can be broken down to distance / time.
If we know Justin drive for 2 hours before lunch and his trip was 5 hours total, then we know he drove for 3 hours at the increased speed.
2 hours * the original speed will give us the distance traveled before lunch, and 3 hours * the increased speed will give us the distance traveled after lunch. The sum of these distances is 330 miles.

2x + 3(x + 10) = 330
5x = 300
The original speed was 60 mph.