HELP ME GUYS I NEEDA GOO GRADE! EASY 10 POINTS

Given the equation f(x)=a(b)x where the initial value is 40 and the growth rate is 20% what is f(4)

When you have 25 numbers, and jake picks 3 random numbers and puts them back, what is the chance bob has of picking those 3 numbers when he picks 6 random numbers (without putting them back)? explain.

Cody was 165cm tall on the first day of school this year, which was 10% taller than he was on the first day of school last year.