Tommy blox borrowed $4000 from a bank at 12% simple interest. after 3 years, he paid back the loan plus the interest. how much did tommy pay back altogether?

The formula we'll use for this is the simple interest formula, or:

Where:

P is the principal amount, $4000.00.
r is the interest rate, 12% per year, or in decimal form, 12/100=0.12.
t is the time involved, 3year(s) time periods.
So, t is 3year time periods.

To find the simple interest, we multiply 4000 × 0.12 × 3 to get that:

The interest is: $1440.00

The answer would be 13.5 minutes.