SOLUTION: Amy walks 1 mph faster than her friend Lisa. In a walk for charity, both walked the full distance of 24 miles. Lisa took 2 hours longer than Amy. What was Lisa's average speed

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Question 36881This question is from textbook Algebra and trigonometry
: Amy walks 1 mph faster than her friend Lisa. In a walk for charity, both walked the full distance of 24 miles. Lisa took 2 hours longer than Amy. What was Lisa's average speed This question is from textbook Algebra and trigonometry

Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website!
Amy walks 1 mph faster than her friend Lisa. In a walk for charity, both walked the full distance of 24 miles. Lisa took 2 hours longer than Amy. What was Lisa's average speed
Amy Data:
distance=24 miles; rate=x+1 mph; time= 24/(x+1) hrs
Lisa Data:
distance=24 miles; rate=x mph; time= 24/x hrs
EQUATION:
Lisa time - 2 hrs = Amy time
24/x -2 = 24/(x+1)
Multiply thru by x(x+1) to get:
24(x+1) - 2x(x+1) = 24(x)
12(x+1)-x(x+1)=12x
12x+12-x^2-x=12x
12-x^2-x=0
x^2+x-12=0
(x+4)(x-3)=0
x=3; the other value of x is negative.
LIsa's average speed was (x+1)= 4mph
Cheers,
Stan H.