Question 698395
Paul made a round trip between two points A and B in 8 hours.
 His speed going up is 9 mph . His speed going down is 18 mph .
 His speed going on a level surface 12 mph.
 What is the distance in miles between A and B?
:
let h = the distance of the hill
let f = the distance of the level surface
:
Write a time equation, time = dist/speed
:
up + lev + lev return + down = 8 hrs
{{{h/9}}} + {{{f/12}}} + {{{f/12}}} + {{{h/18}}} = 8
multiply by 36 to get rid of the denominators, results
4h + 3f + 3f + 2h = 36(8)
Combine like terms
6h + 6f = 288
simplify, divide by 6
h + f = 288/6
h + f = 48 miles, is the distance from A to B