SOLUTION: With the old combine, Nikita's entire wheat crop can be harvested in 72 hours, but a new combine can do the same job in 48 hours. How many hours would it take to harvest the crop w
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Question 783511: With the old combine, Nikita's entire wheat crop can be harvested in 72 hours, but a new combine can do the same job in 48 hours. How many hours would it take to harvest the crop with both combines operating?
Hint: The rate for the old combine is 1/72 crop/hour and for the new one it is 1/48 crop/hour. Together the rate is 1/x crop/hour Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website! With the old combine, Nikita's entire wheat crop can be harvested in 72 hours, but a new combine can do the same job in 48 hours.
How many hours would it take to harvest the crop with both combines operating?
:
An easy way to do this:
let t = time when the two combines work together
Let the completed job = 1
Each combine does a fraction of the job, the two fractions add up to 1 + = 1
least common multiple of these two denominators, 144
144* + 144* = 144*1
Cancel the denominators, resulting in
2t + 3t = 144
5t = 144
t = 144/5
t = 28.8 hr working together
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:
Check this on your calc, enter + =
