## Friday, June 28, 2013

### Frugal Friday--Which is cheaper, 80% or 90% Ground Beef?

Posted by: Rebekah

Picture Credit: mobile-cuisine.com

Our family likes eating lean meat, so when we purchase "fatty" ground beef, we make sure we first cook it and then rinse off (yes, with water) as much of the fat as possible. Consequently, we are left with virtually 100% lean beef.

Taking the above statement into consideration, the question arises: How can you tell which ground beef is cheapest, 80% or  90%?

Let's assume you're at the grocery store, and you find that their 80% ground beef is $2.77/lb. while their 90% is$3.00/bl. Which is really cheaper?

On the surface it appears that the 80% ground beef is cheaper than the 90%; but is this really true?

Okay, let's think about this. What we really want to find is the price of 100% ground beef per pound. Consequently, when we purchase 1lb of 80% beef, we are actually purchasing 80% of 1lb pure beef, and when we purchase 1lb of 90% beef, we are actually purchasing 90% of 1lb pure beef.

Step 1: Find how many pounds of pure beef are actually being purchased

80% beef:  .80 × 1lb = .80lb

90% beef: .90 × 1lb = .90lb

Please note that this step was negligible because 80% of 1lb. and 90% of 1lb. are obviously .80lb. and .90lb respectively.

Step 2: Find how much each pound costs

80% beef: $2.77 ÷ .80lb =$3.46/lb

90% beef: $3.00 ÷ .90lb =$3.33/lb

Conclusion

The 80% ground beef was actually more expensive than the 90% ground beef!

Furthermore, one finds that the formula to find which percentage of meat is lower in price is:

IMPORTANT: The "quantity of meat" must be equal for both meats being compared (i.e. 1lb in the above example).

Please note that the above steps may be used to compare all kinds of ground beef (e.g. 70%, 75%, 85%, 95%). Also note that I am NOT saying 80% is always cheaper than 90%: generally, 80% is in fact cheaper than 90% (but of course not always).