Question

A bus entered the freeway and traveled at a constant speed of 40 mph. 2 hrs later a second bus followed the first bus, entering the freeway from the same spot as the first bus, and traveled at a constant speed of 50 mph. How long will it take the second bus to catch the first??

Answer 1

The second bus catch the first bus after 8 hours

Explanation:

Given as :

The speed of first bus = 40 mph

The first bus start at = T hour

The speed of second bus = 50 mph

The second bus followed first bus after 2 hour = ( T - 2 ) hour

Since distance cover by both buses are same = D

So , Distance = Speed × Time

Or, For First bus , D = 40 mph × T

For second bus , D = 50 mph × ( T - 2 )

I.e 40 × T = 50 × T - 100

or, 100 = 50 × T - 40 × T

Or, 100 = 10 × T

∴ T =
`(100)/(10)` = 10 h

Now since The second bus followed first bus after (T - 2 ) hour = 10 - 2 = 8 h

Hence The second bus catch the first bus after 8 hours Answer