SOLUTION: a loading crew estimates that it can load 8 boxes in 20 mins.at this rate,how many boxes could it load in 1 hr?

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Question 118789: a loading crew estimates that it can load 8 boxes in 20 mins.at this rate,how many boxes could it load in 1 hr?
Answer by bucky(2189) (Show Source):
You can put this solution on YOUR website!
You can do this by setting up a proportion. Start with the ratio of 8 boxes to 20 minutes.
Then notice that an hour is 60 minutes. Since you don't know the number of boxes in 60 minutes
you can set up the ratio of X boxes to 60 minutes. Setting these two ratios equal gives you
the proportion:
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An easy way to work proportions is to cross-multiply ... multiply the numerator on one side
by the denominator on the other side. Then multiply the numerator on the other side by the
denominator on the opposite side. Then set the two products equal.
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Hard to explain, but easy to do. Multiply the 8 (left side numerator) by 60 (right side
denominator) and set this equal to the product you get by multiplying X (right side numerator)
by 20 (left side denominator). In equation form this is:
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Multiplying out the left side results in:
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Finally, you can solve for X by dividing both sides by 20 and you get:
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which simplifies to:
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So in 60 minutes (1 hour) the crew could load 24 boxes.
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You can also do this problem in your head. Just say that if you can do 8 boxes in 20 minutes
then you can do 16 boxes in 40 minutes and adding another 8 boxes in the remaining 20
minutes results in 24 boxes in 60 minutes.
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Hope this helps you to understand this problem a little better.
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