mathematics
posted by Anonymous on .
A person can drive from city A to city B at a certain rate of speed in 6 hours. If she decreases her speed by 10 mph, she can make the trip in 8 hours. How far is it from city A to city B?

first speed  x mph
slower speed  x10 mph
case1 : distance = 6x miles
case2: distance = 8(x10) miles
8(x10) = 6x
2x = 80
x = 40
distance = 6x = 6(40) = 240 miles
check:
8(4010) is also 240