Price per ounce of original bottle

Question

A 23.4 ounce shampoo bottle is labeled "Now 30% more free!" and sells for $15.00.  What is the price per ounce of the original bottle?

Answer 1

We need to know how many ounces are in the original bottle.

 

If x is the original amount, then x + .3x = 23.4 oz

 

1.3x = 23.4

 

x = 23.4\1.3 = 18 oz

 

The price per ounce is $15.00 / 18 oz = $0.84

Answer 2

The bottle says 30% more, so 30% extra is inside the bottle, or 130% of the original size, or 1.3 times as much. We can fit this into the equation:

 

x * 1.3 = 23.4

 

where x is the size of the original. Solving for x, we get 18 as the size of the original, and doing $15/18 oz., we get 0.833, or 83¢ per ounce.