SOLUTION: In a 6-mile run, Cindy finished 15 minutes ahead of Bill. Cindys speed was 2 miles per hour faster than Bills speed. What was Bills speed?

Question 131349: In a 6-mile run, Cindy finished 15 minutes ahead of Bill. Cindys speed was 2 miles per hour faster than Bills speed. What was Bills speed?
Found 2 solutions by checkley71, josmiceli:
Answer by checkley71(8403) (Show Source): You can put this solution on YOUR website!
6/(x+2)+.25=6/x
[6+.25(x+2)]/(x+2)=6/x
[6+.25x+.5]/(x+2)=6/x
(6.5+.25x)/(x+2)=6/x
x(6.5+.25x)=6(x+2)
6.5x+.25x^2=6x+12
.25x^2+6.5x-6x-12=0
.25x+.5x-12=0
(.25x+2)(x-6)=0
x-6=0
x=6 mph is Bill's speed.
6+2=8 Cindy's speed.
proof
6/8+.25=6/6
.75+.25=1
1=1

Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
=distance in mi
=rate in mi/hr
=time in hours

write an equation for both of them
This is Cindy's equation
This is Bill's equation
They ran the same distance, mi.

multiply both sides by

multiply both sides by

Solve by completing the square

only the + root makes sense here
mi/hr answer
check answer:

hr

mi/hr

hr

OK
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