Question

Peter left city a at 9:00 am towards city b at an average speed of 50 mph. Thirty minutes later Emily also leaves city a towards city b. What should be the average speed of Emily if she has to catch-up with peter at 11:30 am?

Answer 1

62.5 mph

Explanation:

Given that :

Peter :

Speed = 50mph

Start Time = 9 a. M

Emily :

Start time = 9:30

Speed = x

In other to catch up at 11:30 :

Peter (11:30 - 9:00) = 2hours 30 minutes = 2.5 hrs

Total distance moved by Peter :

Speed * time = 50 * 2.5 = 125miles

For Emily to cover 125 miles in (11:30 - 9:30) = 2 hours

Speed = distance / time

Speed = 125 miles / 2 hours

Speed = 62.5 miles per hour