Question

Gabriella drives her car 360 miles and averages a certain speed, If the average speed had been 6 mph less, she could have traveled only 330 miles in the same length of time. What is her average speed?

Answer 1

Answer:

72mile/hr

Step-by-step explanation:

Let d be distance in mile

Let r be average rate in mile/hr

Let t be time in hr

d = r × t

t = d/r

360/r = t ........1

Also

The question stated that the average speed was 6 less to travel a distance of 330mile at the same time.

Since the average speed is r, hence 6 less that r = r-6 at the same time

Therefore

330/r-6 = same time ( t ) .......2

Equate 1 and 2

360/r = 330/r-6

Cross multiply

360(r-6) = 330(r)

360r - 360×6 = 330r

360r - 2160 = 330r

Collecting like terms

- 2160 = 330r - 360r

- 2160 = - 30r

Divide both sides by - 30

- 2160/ - 30 = - 30r/ - 30

r = 72mile/hr

Hence the average speed is 72mile/hr