saving pennies

[Littlemike]

Hi. If I saved one cent on January 1st, and 2 pennies on January 2nd, and 3 pennies on January 3rd, and if I continued this progression on what day would I have $1,000 and how much would I have after 365 days? thanks.

 

[tkhunny]

You need this:

\(\displaystyle 1 + 2 + ... + n = \frac{n\cdot(n+1)}{2}\)

Tell us what you get.