3. every 6 months, reuben lopez puts $420 into an account paying 10% compounded semiannually. find the account balance after 15 years. $29,299.53 $27,904.32 $31,500.00 $29,315.00

To solve this we are going to use the future value of annuity due formula: 
where
is the future value
is the periodic deposit 
is the interest rate in decimal form 
is the number of times the interest is compounded per year
is the number of deposits per year

We know for our problem that  and . To convert the interest rate to decimal form, we are going to divide the rate by 100%: . Since Ruben makes the deposits every 6 months, . The interest is compounded semiannually, so 2 times per year; therefore, .
Lets replace the values in our formula:





We can conclude that the correct answer is $29,299.53

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