Question 508431
This is pretty straight forward.  First calculate each workers truck-emptying rate.  You want to add their rates since they will be working together.  However, if their rates are fractions of an hour, you will have to find the lowest common denominator (LCD) so they can be directly added together.
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Jimbo takes 6 hrs to unload a truck, or as a rate, he unloads 1/6 truck per hr
Olaf takes 10 hrs to unload a truck, or as a rate, he unloads 1/10 truck per hr
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To see how much of a truck is unloaded per hr when they work together, we need to add the 1/6 per hr + 1/10 per hr to get a combined rate per hr...
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But 1/6 + 1/10 doesn't easily add, so find the LCD for both (30)...
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1/6 = 5/30
1/10 = 3/30
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5/30 + 3/30 = 8/30, which is the combined unloading rate: .26667 trucks per hour
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To find the total time in hrs, to unload one truck, take the inverse of the rate:
8/30 = the rate
30/8 = time to unload
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30/8 = 3.75 hrs
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Cheers,
Lee