Going average speed of 70mph. Then drop speed to 50 mph it takes 10.8 hours to reach the destination 630 miles away how many hours after the driver started did snow begin to fall

Question

word problem

Answer 1

The trick to this question is if we traveled X amount of time at 70 miles per hour, then we traveled (10.8 - X) amount of time at 50 miles per hour. We can then write the equation like this:

630 (miles traveled) = 70 * X + 50 * (10.8 - X) (Miles per hour times the amount of time spent at that speed)

630 = 70 * X + 540 - 50 * X

90 = 20 * X

4.5 = X

4.5 hours after you started, the snow fell and you had to slow down.