Question 775640: A certain boy going to a certain town 27 miles away rode on a bicycle part of the way and walked the remaining part of the journey. He traveled by bicycle at the rate of 15 miles per hour, and walked at the rate of 4.5 miles per hour. If he covered the whole journey in 2.5 hours, how far did he travel each rate?
Answer by mananth(16946)   (Show Source):
You can put this solution on YOUR website! A certain boy going to a certain town 27 miles away rode on a bicycle part of the way and walked the remaining part of the journey. He traveled by bicycle at the rate of 15 miles per hour, and walked at the rate of 4.5 miles per hour. If he covered the whole journey in 2.5 hours, how far did he travel each rate?
assume he walked x miles
then he rode 27-x miles
d=rt
t=d/r
time walking + time ridding = 2.5 hours
t(walking) = x/4.5
t(riding)= (27-x)/15
x/4.5 + (27-x)/15 = 2.5
to simplify convert to fractions
(2/9)x +(27-x)/15 = 5/2
multiply equation by LCM 45
10x+3(27-x)=(45*5)/2
10x+81-3x=225/2
multiply by 2
20x+162-6x=225
14x=225-162
14x=63
x=4.5
he walked 4.5 miles
you know the rest
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