Please Help with this problem, proportions!

[lillybeth]

Please help with this problem!
Select all that apply.
To decide if 9 cups are greater than 4 pints, thefirst step is to set up a proportion. Which of the following proportions wouldwork?

4 pints/9 cups = 2 pints/x
2 cups/1 pint= 9 cups/x
2 pints/1 cup= 4 pints/x
1 pint/2 cups= 4 pints/x

Thanks guys!

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[JeffM]

Please help with this problem!
Select all that apply.
To decide if 9 cups are greater than 4 pints, thefirst step is to set up a proportion. Which of the following proportions wouldwork?

4 pints/9 cups = 2 pints/x
2 cups/1 pint= 9 cups/x
2 pints/1 cup= 4 pints/x
1 pint/2 cups= 4 pints/x

This involves the ancient arithmetical "rule of three", which says that if you know three numbers in two equal proportions, then you can find the fourth by cross-multiplying. Personally, I would not solve this problem using the rule of three, but you must do what the problem requires. Notice that two of your choices contain a proportion that is a definition of the relationship between a US cup and a US pint.

Which two are they? They give you two numbers that are known to be relevant. Which of them has a third number that is relevant to the problem? So what is the correct answer.

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[lillybeth]

Please help with this problem!
Select all that apply.
To decide if 9 cups are greater than 4 pints, thefirst step is to set up a proportion. Which of the following proportions wouldwork?

4 pints/9 cups = 2 pints/x
2 cups/1 pint= 9 cups/x
2 pints/1 cup= 4 pints/x
1 pint/2 cups= 4 pints/x

This involves the ancient arithmetical "rule of three", which says that if you know three numbers in two equal proportions, then you can find the fourth by cross-multiplying. Personally, I would not solve this problem using the rule of three, but you must do what the problem requires. Notice that two of your choices contain a proportion that is a definition of the relationship between a US cup and a US pint.

Which two are they? They give you two numbers that are known to be relevant. Which of them has a third number that is relevant to the problem? So what is the correct answer.

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Thanks Jeff, i already figured it out, b annd d. thanks!

 

[HallsofIvy]

To decide if 9 cups are greater than 4 pints, thefirst step is to set up a proportion. Which of the following proportions would work?

One fact that you need to know to answer this question, that you do not mention, is that "two cups equals one pint"!
That's why one of the proportions has the fraction "2 cups/one pint". It is a "unit fraction". Since there are two cups in one pint, "2 cups" and "1 pint" are the same so that fraction is equal to 1.

 

[lillybeth]

One fact that you need to know to answer this question, that you do not mention, is that "two cups equals one pint"!
That's why one of the proportions has the fraction "2 cups/one pint". It is a "unit fraction". Since there are two cups in one pint, "2 cups" and "1 pint" are the same so that fraction is equal to 1.

Thank you.