How do you solve with the correct converting

Question

jenna brought a 2-liter bottle of orange soda to share with her friends for her birthday. She brought cups that each held about 225 milliliters. How many cups could Jenna fill?

Answer 1

Jenna,

 

The question of "cups" in this story problem is NOT the same as "cups" in American Standard Measurement. Remember to keep you units in Metric, and your solution will be very easy to find.

 

You were correct, too, that it IS Metric conversion, and you don't have to worry about drawing pictures or what the weight equivalent is. I apologize for the confusing answers previously shared.

 

That being said, there are 1000 milliliters in a liter. Therefore, there are 2000 milliliters in a 2-liter bottle of liquid.

 

All you have to do is divide 2000 milliliters (your2-liter bottle) by 225 milliliters (the size of your cups) to find out how many cups you can fill.

 

Best of luck.

 

Jane

Answer 2

You could use conversions to solve this problem.  The "conversion factor" to use here is "225 mL / 1 cup".

You'll also need to do a mL↔L conversion, using "1000 mL / 1 L".

 

So you start with the amount of soda that you've got (because all the other numbers in this problem are conversion factors.  You've got 2 L of soda.  So here goes:

 

2 L soda x (1000 mL / 1 L) x (1 cup / 225 mL) = 9 cups.

 

Seeing this sort of set-up should bring confidence that you've done the conversions correctly, because all of the units cancel except "cups."  

 

Note: You probably won't want all of the cups to be completely full, so an answer of 9 cups is perfectly reasonable, and they'd all be full enough.  We round to one digit in the answer, because 2 L has only one digit.

Answer 3

Dear Taryn,

This is not a question about converting. Why don't you draw a picture (diagram) of a 2 L bottle of soda, and a set of much smaller 225 mL cups (oh, I see, it's a question about the prefixes in the metric system that scale your units) = 0.225 L each. Then you'll see that it's just a simple division problem, how many times does 0.225 L "go into" 2 L. You can do that math, I think.

-- S.

P.S. By the way, have you ever actually tested packaged foods for their actual weights and volumes? By law, they're required to have at least the amount labeled -- do they? Note: For sodas, you need to measure after decarbonating (allowing all the gas to bubble out) the liquid -- otherwise, bubbles will form in your graduated cylinder (etc.) and give you erroneously high volume readings. But, does the volume of the liquid change when you decarbonate it? That's a really good (=science fair material!) question, and not too easy to measure!