Question 515269
A long distance truck driver traveled 160 miles in one direction during a snow storm.
 The return trip in rainy weather was accomplished at double the speed and took 4 hours less time.
Find the speed going. 
:
First find the time.
let t = travel time required in snow
then
(t-4) = time required in rain
:
Write a speed equation: s = dist/time
:
Rain speed = twice snow speed
{{{160/((t-4))}}} = {{{2(160/t)}}}
{{{160/((t-4))}}} = {{{320/t}}}
Cross multiply
320(t-4) = 160t
320t - 1280 = 160t
320t - 160t = 1280
160t = 1280
t = {{{1280/160}}}
t = 8 hrs required thru the snow, then 4 hrs thru the rain
:
Find the speeds
160/8 = 20 mph thru snow
160/4 = 40 mph thru rain