Question

The family trip to Grandma's consisted of both a train ride and a car ride. The average speed of the train ride was 68 miles per hour, and the average speed of

the car ride was 64 miles per hour. The entire trip lasted 7 hours.
Let .x be the number of hours the train ride lasted. Write an expression for the total distance of the trip, in miles.
total distance (in miles)

Answer 1

Total distance of trip = 4x + 448 miles

Explanation:

Let x = number of hours train ride lasted

Total distance by train at an average speed of 68 mph for x hours

= 68x miles

If x hours was the train ride, then 7- x hours must be the car ride since the total trip took 7 hours

Total distance by car at average speed of 64 mph for (7-x) hours

= 64(7-x)

= 64 x 7 - 64x

= 448 - 64x miles

Total distance by both train and car = sum of the two distances

= 68x + 448 - 64x

= 4x + 448