SOLUTION: Bart can peel a batch of 3000 lbs of apples in 12 hours with an old machine, while Mona can do the same job in 8 hrs using the new machine. If Bart starts peeling at 8am and Mona j

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Bart can peel a batch of 3000 lbs of apples in 12 hours with an old machine, while Mona can do the same job in 8 hrs using the new machine. If Bart starts peeling at 8am and Mona j      Log On


   



Question 829334: Bart can peel a batch of 3000 lbs of apples in 12 hours with an old machine, while Mona can do the same job in 8 hrs using the new machine. If Bart starts peeling at 8am and Mona joins him at 9am then at what time will they finish the batch working together. So far I have 1/t1+1/t2=1/t3 so that is 1/12+1/8=1/x
2x+3x=24
6x=24
x=4 but I am clueless as to what I am supposed to do with the extra hour Bart has?

Found 2 solutions by josgarithmetic, MathTherapy:
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
Let's start from here, the correct equation for their combined rate: 1%2F12%2B1%2F8=1%2Fx.

2%2F24%2B3%2F24=1%2Fx... but instead of solving for x, just compute the rate. That is what you really want, even if it is as a rational number, fraction form.

That is highlight_green%285%2F24%29 batches per hour.
You can also say, 5 batchs in 24 hours.

Next, look at time values, not necessarily viewed on a number line. Time 8AM is time, ZERO. Let h be the time after the first hour, because Mona joins Bart after ONE hour. Bart works for 1+h hours and Mona works with him for h hours.

The total jobs done will be 1.
This one job is jobByBart%2BjobByBoth=1;
highlight_green%28highlight%28%281%2F12%29%2A1%2B%285%2F24%29%28h%2B1%29=1%29%29
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Most important is to understand the analysis, and the resulting equation. Solving it for h should be much less of a chore.

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!

Bart can peel a batch of 3000 lbs of apples in 12 hours with an old machine, while Mona can do the same job in 8 hrs using the new machine. If Bart starts peeling at 8am and Mona joins him at 9am then at what time will they finish the batch working together. So far I have 1/t1+1/t2=1/t3 so that is 1/12+1/8=1/x
2x+3x=24
6x=24
x=4 but I am clueless as to what I am supposed to do with the extra hour Bart has?
You need to realize that Bart can do the job in 12 hours, or 1%2F12, of job in 1 hour
Therefore, in 1 hour (8:00 AM - 9:00 AM), he has completed 1%2F12 of the job, which leaves 11%2F12 to be completed
by he and Mona.
Working together to complete the 11%2F12 remaining work, you should get 4.4 hours, or 4%262%2F5 hours, or 4 hours, 24 minutes,
after both start (9:00 AM), which makes the end-time: highlight_green%2813%3A24_HOURS%29, or highlight_green%281%3A24_PM%29
You can do the check!!
If you need a complete and detailed solution, let me know!!
Send comments, “thank-yous,” and inquiries to “D” at MathMadEzy@aol.com.
Further help is available, online or in-person, for a fee, obviously.

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