Question 243990
A person runs 3 miles and walks 2 miles.
 He runs twice as fast as he walks and finishes in exactly one hour.
 How fast does he walk.
:
let r = walking speed
then
2r = running speed
:
Write a time equation time = dist/rate
Walk time + run time = 1 hr
{{{2/r}}} + {{{3/(2r)}}} = 1
Multiply by 2r
2(2) + 3 = 2r
4 + 3 = 2r
r = {{{7/2}}}
r = 3.5 mph walking rate
:
:
Check solution
2/3.5 + 3/7 = 1