Math CentralQuandaries & Queries


Subject: Doubling money
Name: Pat
Who are you: Parent

Take $.01 and double it every day for 30 days. How many dollars would you have?

Thank you so much

Hello Pat. I always hear about kids getting their parents to agree to this for their allowance - poor parents!

On the first day, you have $0.01.
On the next day, you have $0.01 x 2.
On the next day, you have $0.01 x 2 x 2.
and so on...
On the nth day, you have $0.01 x 2n-1.

So on the 30th day, you have $0.01 x 229 = $5 368 709.12

That's the power of compound interest! It is equivalent to 100% interest per day paid daily. On even a penny as your initial investment, it climbs immediately to unfathomable heights!

Stephen La Rocque.>

About Math Central


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences.
Quandaries & Queries page Home page University of Regina PIMS