Find the total amount to be paid back (that is,loan + interest) on this loan.

500 for 2 weeks at 100 interest per week.

2 answers

You did not give me my answer
impatient much?
Just use your formula.
Assuming that "100" means 100% (that's some interest!) that would be.
500(1 + 1.00)^2 = 2000