SOLUTION: Shelly can cut a lawn with a riding mower in 4 hours less time than it takes William to cut the lawn with a push mower. If they can cut the lawn in 8 hours working together find ho

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Shelly can cut a lawn with a riding mower in 4 hours less time than it takes William to cut the lawn with a push mower. If they can cut the lawn in 8 hours working together find ho      Log On


   

Question 1127050: Shelly can cut a lawn with a riding mower in 4 hours less time than it takes William to cut the lawn with a push mower. If they can cut the lawn in 8 hours working together find how long to the nearest tenth of an hour it takes for William to cut the lawn alone.
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
Lawn Per Hour:
Shelly, 1%2F%28x-4%29
William, 1%2Fx
Combined, 1%2F8
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1%2F%28x-4%29%2B1%2Fx=1%2F8

8%28x%2Bx-4%29=x%28x-4%29

16x-32=x%5E2-4x

x%5E2-20x%2B32=0

x=%2820%2B-+sqrt%28400-4%2A32%29%29%2F2

x=%2820%2B-+sqrt%28272%29%29%2F2
x=%2820%2B-+2%2Asqrt%2868%29%29%2F2
x=10%2Bsqrt%2868%29

x=1.7538, or, x=18.2462


Nearest tenth of an hour:
18 hours 12 minutes