Question

The browns are moving across the counrty. Mr. Brown leaves 2.5 hours before Mrs. Brown, if he averages 75 mph and she averages 85 mph, how many hours will it take Mrs. Brown to catch up to Mr. Brown?

Answer 1

the time taken by Mrs Brown to catch up is 18.75 hours

Explanation:

Given;

average speed of Mr Brown = 75 mph

average speed of Mrs Brown, = 85 mph

time first traveled by Mr Brown = 2.5 hours

The distance traveled by Mr Brown before Mrs Brown start her own Journey;

D = speed x time

D = 75 mph x 2.5 h

D = 187.5 miles

Let the time taken by Mrs Brown to catch up = t

(85 - 75)t = 187.5

10t = 187.5

t = 18.75 hours

Check:

after 18.75 hours: Mrs Brown will travel ⇒ 18.75 x 85 = 1593.75 miles

after (2.5 h + 18.75h) : Mr Brown will travel ⇒ 21.25 x 75 = 1593.75 miles