SOLUTION: One person can do a job in 8 hours. A second person can do it in 12 hours. If the first person works 2 hours less than the second, how many hours will it take them working together
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Question 91870This question is from textbook algebra and trigonometry
: One person can do a job in 8 hours. A second person can do it in 12 hours. If the first person works 2 hours less than the second, how many hours will it take them working together? PLEASE HELP This question is from textbook algebra and trigonometry
You can put this solution on YOUR website! One person can do a job in 8 hours. A second person can do it in 12 hours. If the first person works 2 hours less than the second, how many hours will it take them working together?
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One person DATA;
Time = 8 hr/job ; Rate = 1/8 job/hr
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Second person DATA:
Time = 12 hr/job ; Rate = 1/12 job/hr
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Time on this job:
2nd person works x hours.
1st person works x-2 hours.
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EQUATION:
x(1/12) + (x-2)(1/8) = 1 job
Multiply thru by 24 to get:
2x + 3(x-2) = 24
2x + 3x-6 = 24
5x = 30
x = 6 hrs (how long 2nd person works)
x-2 = 4 hours (how long 1st person works)
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Cheers,
Stan H.
You can put this solution on YOUR website! Assume it takes them T hours working together.
then in one hour the first person can finish
the second person can finish in the same one hour
working together, the first person will spend T-2 hours, the second person will spend T hours
the portion finished by first person is
the portion finished by second person is
together they finish the whole thing represented by 100% which is 1
so we have
multiply both sides by 24 we get
3(T-2) + 2T = 24
solve this equation we get T = 6 hrs.
( I assume you know how to solve one variable equation)
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