Bob deposited $25k in a savings account @ 10% interest compounded semiannually. At the beginning of year 4 he deposited another $40k @10% compounded semiannually. At the end of 6yrs, what is the balance in his account? I have worked it out several ways, but now I am unsure of which way to go....(Worried)

3yrsx2=6 periods

10% /2=5%

25000x1.7716 (per table in my book)=44290-25000=$19290 interest for 4yrs off $25000

2yrsx2=4 periods

40000x1.4641=58564-40000=18564 interest for 2 yrs off $40000

25000+40000+19290+18564=102,854

I also worked it out this way.......

4yrsx2=8 periods; 5%

25000x2.1436(book table)=53590-25000=$28590 interest for 4 yrs off $25000

40000x1.4641=5864-40000=18564 interest for 2yrs off $40000

25000+40000+28590+18564=$112154