HELP! I HAVE BEEN STUCK FOR HOURS! In a large marathon, runners start the race in stages. Leanna started in group E and ran at a rate of 4.8 miles per hour. During the race she was passed by Irina who ran at a rate of 5 miles per hour and started in group H, 20 minutes after Leanna started. How far did Leanna run before she was passed by Irina?

Respuesta :

Answer: Leanna ran 40.08 miles before she was passed by Irina.

Step-by-step explanation:

Let t represent the number of hours that Leanna ran before she was passed by Irina.

Leanna started in group E and ran at a rate of 4.8 miles per hour.

Distance = speed × time

Distance that Leanna ran in t hours is

4.8 × t = 4.8t

During the race, she was passed by Irina who ran at a rate of 5 miles per hour and started in group H, 20 minutes after Leanna started. 20 minutes = 20/60 = 1/3 hours. This mean that the number of hours that Irina ran before she passed Leanna is (t - 1/3) hours.

Distance that Irina ran would be

5(t - 1/3) = 5t - 5/3

Since they covered the same distance, then

4.8t = 5t - 5/3

5t - 4.8t = 5/3

0.2t = 1.67

t = 1.67/0.2 = 8.35 hours

Distance that Leanna ran before she was passed by Irina is

4.8t = 4.8 × 8.35 = 40.08 miles