Question 970620
P=Po * {1 + (r/n)}^nt    P=money at the end    Po= principal at beginning.

P= $750 *  {1 + (.08)}^7   n=1, so it does neither affects r/n  nor affects nt

{1.08}^7= 1.7138

P=$1285.36

You can't easily check this, but 72/interest rate    = time in years it takes money to double.

72/8  = 9 years for doubling.

The money should not have doubled yet, and it hasn't.  The formula above works for continuously compounding interest, but it is a rough way to check.