SOLUTION: It takes a boy 90 minutes to mow his parents lawn, but his brother can do it in 60 minutes. how long would it take them to mow the lawn if they worked together using two lawnmowers

Question 297383: It takes a boy 90 minutes to mow his parents lawn, but his brother can do it in 60 minutes. how long would it take them to mow the lawn if they worked together using two lawnmowers?
Answer by richwmiller(17219) (Show Source): You can put this solution on YOUR website!
three ways to solve
a)
x/90+x/60=1
x=36
b)x/(90/60)+x/(60/60)=1
x=3/5
3*60/5=3*12=36
c)
90/60=3/2
60/60=1
x/(3/2)+x/(1)=1
2x/3+x=1
2x+3x=3
5x=3
x=3/5
3*60/5=3*12=36

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