Rational expression please help

If there are 12 moths and some have 31 days and others have 30 days how many have 28 days?

How to find the exponential function y=ca^x, with points (1,2) and (2,1)

Acolony contains 1500 bacteria. the population increases at a rate of 115% each hour. if x represents the number of hours elapsed, which function represents the scenario? f(x) = 1500(1.15)" f(x) = 1500(115) f(x) = 1500(2.15) f(x) = 1500(215)