math
posted by yeah .
If $3000 is deposited at the end of each half year in an account that earns 6.2% compounded semiannually, how long will it be before the account contains $130,000?

and what is your thinking?

3000(1.031^n  1)/.031 = 130000
1.031^n  1 = 1.3743333
1.031^n = 2.3743333
n log 1.031 = log 2.3743333
n = 28.32 halfyears or appr. 14 years