Dear Sir or Madam:

If I buy something for $10 and want to sell for 25% more, do I multiply by 1.25 or divide by .75? Or another way - why do I get $13.33 when dividing by .75 ?

Thank you for your time,

Charlie

Hi Charlie,

There is part of your first question that is implicit, but if it were there I think the answer would be clear. What I see is

If I buy something for $10 and want to sell for 25% more than I bought it for, do I multiply by 1.25 or divide by .75? You bought it for $10.00, and 25% of $10.00 is $2.50. Hence you want to sell it for $10.00 + $2.50 = $12.50. In other words 1.25  $10.00.

Dividing by 0.75 gives you the answer to an entirely different question. Suppose that you bought it from Sam for $10.00 and sold it to Fred for some amount that you didn't tell Sam. Sam asked Fred "What did you pay for it?" Fred answered "You got 75% of what I paid". That is the $10.00 that Sam got was 75% of what Fred paid. Hence

$10.00 = 0.75 (what Fred paid)

When you have a percentage question you really need to ask "percentage of what?"

Go to Math Central