SOLUTION: On a trip to San Diego, Dad drove 32 mi in
heavy LA traffic and 140 mi in light traffic. The
average speed is 3 times as fast in light traffic as
that in heavy traffic. The e
Question 1188281: On a trip to San Diego, Dad drove 32 mi in
heavy LA traffic and 140 mi in light traffic. The
average speed is 3 times as fast in light traffic as
that in heavy traffic. The entire trip takes 3 hrs;
determine the driving speeds.
Found 2 solutions by ankor@dixie-net.com, josgarithmetic:Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website! On a trip to San Diego, Dad drove 32 mi in heavy LA traffic and 140 mi in light traffic.
The average speed is 3 times as fast in light traffic as that in heavy traffic.
The entire trip takes 3 hrs; determine the driving speeds.
:
let s = speed in heavy traffic
then
3s = speed in light traffic
:
Write a time equation, time = dist/speed
:
heavy traf time + light traf time = 3 hrs + = 3
multiply equation by 3s, cancel denominators
3(32) + 140 = 3(3s)
96 + 140 = 9s
236 = 9s
s = 236/9
s = 26.22 mph in heavy traffic
and
3*26.22 = 78.66 mph in light traffic
:
:
:
Check
32/26.22 = 1.22 hrs
140/78.66 = 1.78 hrs
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total time 3 hrs Answer by josgarithmetic(39620) (Show Source): You can put this solution on YOUR website!
SPEED TIME DISTANCE
Heavy Traffic r 32/r 32
Light Traffic 3r 140/(3r) 140
TOTAL 3