Question 382486
tim and brad are building a racecar.tim can build the car in 2 months less time than brad.together they can do the job in 7 months.how long will it take each of them if they work alone? give your answer to the nearest tenth...
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brad time = x months
tim time = x-2 months
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brad rate = 1/x job/month
tim rate = 1/(x-2) job/month
together rate = 1/7 job/month
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Equation:
rate + rate = together rate
1/x + 1/(x-2) = 1/7
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Solve for "x" and "x-2".
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Multiply thru by 7x(x-2) to get:
7(x-2)+7x = x(x-2)
7x-14 = x^2-2x
x^2-9x+14 = 0
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(x-2)(x-14) = 0
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Only usable solution:
x = 14 months (Time for "brad".)
x-2 = 12 months (Time for "tim".)
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Cheers,
Stan H.
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Cheers,
Stan H.