You deposit $10 per month in a bank that offers an annual interest rate of 6%. at the end of three years, your balance is:

An easy way to do this is to first figure out the amount of money you deposited total for the first year. 10$ per month would mean 120$ in the first year. With an annual interest rate of 6%, you will increase 120$ by 6%. Which is about $7.20. So now you will have $127.20 for the first year. Then you will add another 120$ to that (10$ a month) for your second year. and you should now have $247.20. 6% of 247.20 is about 14.8. So you will add that as well, which will give you 262 for your second year. Finally you will add another 120$ for your third year and you will get 382. Another addition of 6% of that (which is about 22.9, or 23) and you should now have $404.90.

2x+10=36. x being the number of friends.