SOLUTION: A man rode a bicycle for 12 miles then hiked an additional 8 miles. The total time for the trip was 5 hours. If his rate when he was riding the bicycle was 10 mph faster than his r

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Question 1010637: A man rode a bicycle for 12 miles then hiked an additional 8 miles. The total time for the trip was 5 hours. If his rate when he was riding the bicycle was 10 mph faster than his rate walking, what was each rate?
Found 2 solutions by josgarithmetic, MathTherapy:
Answer by josgarithmetic(39614) About Me  (Show Source):
You can put this solution on YOUR website!
The same question happens as different examples. This table shows this as a generalization.

The description could be, man rode a bicycle for b miles then hiked an additional h miles.
The total time for the trip was T hours. If his rate when he was riding the bicycle was k mph
faster than his rate walking, what was each rate?

             rate          time         distance

BIKE         r+k           x              b

HIKE          r            y              h

Total                      T


The given variables are system%28h%2Ck%2Cb%2CT%29.
The unknown variables are system%28x%2Cy%2Cr%29.

Using the basic travel rates rule, x and y can be put into expressions.
system%28x=b%2F%28r%2Bk%29%2Cy=h%2Fr%29.

The given total time T fits with an equation,
x%2By=T
highlight%28b%2F%28r%2Bk%29%2Bh%2Fr=T%29

Solve the red-outlined equation for r.

Answer by MathTherapy(10549) About Me  (Show Source):
You can put this solution on YOUR website!

A man rode a bicycle for 12 miles then hiked an additional 8 miles. The total time for the trip was 5 hours. If his rate when he was riding the bicycle was 10 mph faster than his rate walking, what was each rate?
Let riding speed be S
Then hiking speed = S – 10
Time spent riding: 12%2FS
Time spent hiking: 8%2F%28S+-+10%29
With total tiem being 5 hours, we get: 12%2FS+%2B+8%2F%28S+-+10%29+=+5
12(S – 10) + 8S = 5S(S – 10) ------- Multiplying by LCD, S(S – 10)
12S+-+120+%2B+8S+=+5S%5E2+-+50S
20S+-+120+=+5S%5E2+-+50S
5S%5E2+-+50S+-+20S+%2B+120+=+0
5S%5E2+-+70S+%2B+120+=+0
5%28S%5E2+-+14S+%2B+24%29+=+5%280%29
S%5E2+-+14S+%2B+24+=+0
(S - 12)(S - 2) = 0
S, or riding speed = highlight_green%2812%29 mph OR S = 2 (ignore)
Hiking speed: 12 – 10, or highlight_green%282%29 mph