SOLUTION: a man rode a bike for 12 miles and hiked 8. The total time for the trip was 5 hours. If his rate when he was riding a bike was 10mph faster than his rate walking, what was each rat

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Question 32403: a man rode a bike for 12 miles and hiked 8. The total time for the trip was 5 hours. If his rate when he was riding a bike was 10mph faster than his rate walking, what was each rate?
Answer by Paul(988) About Me  (Show Source):
You can put this solution on YOUR website!
 X=WALKING SPEED

X+10=RIDING SPEED

Eqaution:



Cross multiply:

12(x)+8(x+10)=5[(x)(x+10)]

20x%2B80=5%28x%5E2%2B10x%29

5x%5E2%2B30x-80=0

x%5E2%2B6x-16=0

x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ 

a=1, b=6, c=-16

x+=+%28-6+%2B-+sqrt%28+6%5E2-4%2A1%2A-16+%29%29%2F%282%2A1%29+ 

Simplfy:

x=-8 or x=2

remove negative x=2

2+10=12

Hence, his walking speed was 2mph and his bike speed was 12 mph.

Paul.