How many different five-digit codes are possile if the digits cannot be repeated?

Can someone answer this question? : )

How many $20 bills do you need to have to make $280

A. use the formula for continuous compounding with the original example: $1000 invested at 2% for 1 year. record the amount to 5 decimal places. use a calculator. b. compare it to the result using the original compound interest formula with n = 365 calculated to 5 decimal places. which has a larger value? explain.