Compound Interest

[interest23]

When Tonya was born, her grandparents invested $10,000 at 5% per year, compounded semi-annually, to pay for her edcuation.
What was the investment worth on Tonya's Twelfth birthday?

[HallsofIvy]

When Tonya was born, her grandparents invested $10,000 at 5% per year, compounded semi-annually, to pay for her edcuation.
What was the investment worth on Tonya's Twelfth birthday?

If you are expected to do a problem like this (and I can't imagine a reason for doing such a problem if it were not homework) then you must be expected to know a formula for it!

Here is the formula you need (though I expect it is in your textbook- and, knowing today's textbook set in a separate "box" with bright colors!):

If S dollars are invested at annual interest rate i, for n years, and compounded m times a year, then the Value is
V= S(1+ i/m)^(nm).

In your problem, S= 10000, i= 0.05, n= 12, m= 2.