Question

Enrique leaves his house and starts to run at an average speed of 6 miles per hour. Half an hour later, Enrique’s younger (and faster) brother leaves the house to catch up to Enrique running at an average speed of 8 miles per hour. How long will it take for Enrique’s brother to run half the distance that Enrique has run?

Answer 1

t= 0.8 hr or 48 min.

Explanation:

Speed of Enrique= 6 mph

Half and hour late it means that after 1/2 hr.

Speed of Enrique brother = 8 mph

Lets take Enrique cover x distance in time t hr .

So

x = 6 t ------------ 1

Then his brother will cover x/2 distance in time (t-1/2) hr.

So

x/2 = 8 (t-1/2) -----------------2

Now from equation 1 and 2

6 t = 16 (t-1/2)

6 t = 16 t - 8

So t= 0.8 hr or 48 min.

It means that his brother will take 0.8 hr to cover half of distance cover by Enrique .