SOLUTION: Twin brothers, Billy and Bobby, can mow their grandparent's lawn together in 92 minutes. Billy could mow the lawn by himself in 25 minutes less time that is would take Bobby. How l

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Question 902254: Twin brothers, Billy and Bobby, can mow their grandparent's lawn together in 92 minutes. Billy could mow the lawn by himself in 25 minutes less time that is would take Bobby. How long would sit take Bobby to mow the lawn by himself?
Answer by ewatrrr(24785)   (Show Source): You can put this solution on YOUR website!
|Multiplying thru by 92x(x-25)so as all denominators = 1
92(x-25) + 92x = x(x-25)
x^2 -209x + 2300 = 0
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation (in our case ) has the following solutons:



For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

Discriminant d=34481 is greater than zero. That means that there are two solutions: .




Quadratic expression can be factored:

Again, the answer is: 197.345301442776, 11.6546985572237. Here's your graph:
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