Question

Jeff is traveling from his home in Salem at a constant rate of 50 mph. He has already traveled 20 miles. His sister Jennifer is making the same trip but at a constant rate of 60 mph and has only traveled 5 miles. How long will it take Jennifer to catch Jeff.
A) 1.5
B) 3
C) 1
D) 95

Answer 1

Answer    

Find out the  how long will it take Jennifer to catch Jeff.

To prove

Formula

$Speed = \frac{Distance}{Time}$

let us assume that the distance be denoted by d .

let us assume that the time be denoted by t .

As given

Jeff is traveling from his home in Salem at a constant rate of 50 mph.

He has already traveled 20 miles .

As put the values in the formula

$50 = \frac{d + 20}{t}$

50t - 20 = d

(As jeff already travelled 20 miles distance.)

As given

His sister Jennifer is making the same trip but at a constant rate of 60 mph and has only traveled 5 miles.

than put the value in the formula

$60 = \frac{d +5}{t}$

than the equation becomes

60t -5 = d

Than the two equation becomes

50t - 20 = d and 60t -5 = d

compare both the equation

50t - 20 = 60t -5

50t - 60t = 20 -5

- 10t = 15

$t = \frac{-15}{10}$

t = -1.5

(As time cannot be negative.)

t = 1.5 hours

1.5 hours will it take Jennifer to catch Jeff.

Option (A) is correct .