Bill spends two days driving from point a to point b . on the first day, he drove 2 hours longer and at an average speed 5 miles per hour faster than he drove on the second day. if during the two days he drove a total of 680 miles over the course of 18 hours, what was his average speed on the second day, in miles per hour?

average speed on the second day is 35 mph

Explanation:

given data

time = 2 hour

speed = 5 miles per hour

total distance = 680 miles

total time = 18 hours

to find out

average speed on the second day

solution

according to question

day 1 , he drive 2 hour longer

so we consider x hours driving on day 2

so on day 1 he drive x + 2

so

we can say total drive = 18 hours that mean

18 = x + (x + 2)

so that  x  = 8

so we say

day 1 he drive =  (8+2) =  10 hours

and day 2 he drive = 8 hours

and

now we consider day 2 speed =  x

so day 1 speed will be  = x + 5

and

we know that total distance = 680

and distance = speed × time

so we say

680 = x (8)  + ( x + 5 ) (10)

680 = 18 x + 50

so x  = 35

so that average speed on the second day is 35 mph