Math CentralQuandaries & Queries


Question from Chris, a parent:

I am trying to figure out how much more volume is needed to reach a certain %. For example if I sell 15,182 of unit X out of 43,241 total units. Then I know that unit X is 35.1% of units sold. However, I need to get unit X to be 46.3% of total units sold. I need to figure how many more units of X I need to sell to reach this %. Of course if I sell more units of X then this increases the denominator. Can you please help? Thank you for your time.

Hi Chris,

To arrive at 35.1% as the percentage of unit X sold you performed the calculation

15,182/43,241 X 100

The question you ask is an ideal place to use a little algebra. Suppose that you sell z additional units of unit X and this results in 46.3% of the total units sold being unit X. The total sold is then 43,241 + z and the number sold of unit X is 15,182 + z. Using the same calculation as above you would have


Solve for z.

If you need additional help write back,

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