Question

Suppose that you have a goal to drive two miles at an average rate of 60 miles per hour (mph). During the first mile you travel at a rate of 30 mph. How fast would you need to travel during the second mile in order to reach your goal of 60 mph for the total two-mile distance? (Remember rate is found by taking distance divided by time.)

Answer 1

Answer: 30 mph.

Total speed = S1 + S2 

where total speed is for the average speed goal (60m ph), S1 is the speed for the first mile (30 mph) and S2 is for speed for the second mile which is unknown. To solve, simply subtract S1 from total speed.

60 mph - 30 mph= 30 mph