Proportions

Some students have trouble with setting up proportions and how to solve.  Here is an example to help you out.


My mother is having a party and we were trying to figure out how much we would need to buy soda and how much we would be sending.  One store had a case of 12 cans on sale for $4.99.  The other store had a case of 24 cans on sale for $9.80 .  We need to buy 48 cans and wanted to go to the store that we would pay the least.

Store #1.
12/4.99 = 48/X
12X = 4.99 * 48
12X = 239.52
X= 19.96  So in Store #1, we would spend $19.96 for 48 cans of soda.
Store #2
24/9.99 = 48/X
24X= 9.80 *48
24X = 470.40
X= 19.60  So in Store #2 we would spend $19.60 for 48 cans of soda.
Store #2 is cheaper.