SOLUTION: Twin​ brothers, Billy and​ Bobby, can mow their​ grandparent's lawn together in 73 minutes. Billy could mow the lawn by himself in 35 minutes less time that it would take Bo

Algebra ->  Human-and-algebraic-language -> SOLUTION: Twin​ brothers, Billy and​ Bobby, can mow their​ grandparent's lawn together in 73 minutes. Billy could mow the lawn by himself in 35 minutes less time that it would take Bo      Log On


   

Question 1145948: Twin​ brothers, Billy and​ Bobby, can mow their​ grandparent's lawn together in 73 minutes. Billy could mow the lawn by himself in 35 minutes less time that it would take Bobby. How long would it take Bobby to mow the lawn by​ himself?
Answer by ikleyn(52781) About Me  (Show Source):
You can put this solution on YOUR website!
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Let x = "How long would it take Bobby to mow the lawn by​ himself", i.e. the unknown value under the question.


Then your basic equation is 


    1%2Fx + 1%2F%28x-35%29 = 1%2F73.


saying that


    Bobby's rate of work + Billy's rate of work = combined rate of work.



It is your basic equation. Solve it.



The first step is multiplying both sides by 73*x*(x-35).


After that reduce the equation to the standard form quadratic equation and solve by any method (factoring or quadratic formula).