Question

Two truck drivers leave a rest area on the interstate at the same time. One truck travels east, and the other one travels west.

The truck heading west has an average speed of 70 mph, and the truck heading east has an average speed of 60 mph. How

long will they travel before they are 325 miles apart?

2.5 hours.

Step-by-step explanation:

Let the distance traveled by the truck heading west = x miles.

Let the distance traveled by the truck heading east = y miles.

Distance between the trucks = 325 miles.

Therefore, x + y = 325 (Equation 1).

Speed of the truck heading west = 70 miles per hour.

Speed of the truck heading east = 60 miles per hour.

Therefore, time taken by the truck heading west = x/70 hours and time taken by the truck heading east = y/60 hours.

Since the time is same for both trucks, therefore:

x/70 = y/60.

6x = 7y.

x = 7y/6 (Equation 2).

Put Equation 2 in Equation 1:

7y/6 + y = 325.

(7y + 6y) / 6 = 325.

13y = 1950.

y = 150 miles.

Since time taken by the truck heading east = y/60 hours, put y = 150 miles.

Time taken = 150/60 hours.

Time taken = 2.5 hours.

Therefore, the trucks will travel 2.5 hours before they are 325 miles apart!