Many times people say: “I don’t need to learn Algebra! When will I ever use it?!” Well yesterday I was at the local grocery market and saw an extremely good example based on the sour cream that was on sale. I entered a cookie competition so I needed roughly 48 ounces of sour cream and had two choices to choose from. Either I could get a few little tubs or one big tub. The little tub was 16 ounces whereas the big tub was exactly 48 ounces.

First question – How many little tubs of sour cream would I need in order to have 48 ounces of sour cream?

Let x = amount of tubs.

We know each small tub had 16ounces. Therefore, if we got one tub it would 16*1 = 16, if we got two it would be 16*2 = 32 etc. So how many tubs (x) do I need?

16*x =48

x= 48/16

x=3

Answer: We need to get 3 tubs!

Second question – Is it cheaper to get three tubs of sour cream or one big tub?

Well as we saw it said for the small tub of 16 ounces it was $1.99. Therefore since we need three tubs our total is:

3 *$1.99=$5.97

Remember for one big tub it was $6.99.

Answer: It is cheaper to get three small tubs than one big tub!

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Another way of doing this is by looking at the price per ounce. I do not know if many stores have the price per ounce (the number in the yellow bubble on the bottom far right corner) but this is handy way to quickly see the value of what you are getting very quickly

Third question – How is price per ounce calculated?

For the 16 ounce tub we know that the price was $1.99. So how much did every ounce cost?

1.99/16=12.5 cents per ounce

(Notice that when it comes to owing money everything seems to always round up)

For the 48 ounce tub we know that the price was $6.99. So how much is every ounce cost?

6.99/48= 14.6 cents per ounce

Answer: Price per ounce = Total Cost / how many ounces.

As you can see that was a quick way to see that no matter how many tubs we bought, buying the little ones would be cheaper. One interesting side point, my sister sent me back to the store roughly 4 hours later and every single little tub of sour cream was sold!!

**Wala that was Algebra!!!!** Please keep this in mind when you go to places like Costco because you would be amazed – sometimes it really isn’t that great of a deal ☺