with work shown please

Suppose there are 90 bacteria in a Petri dish at start time. Ten hours later, there are 210 bacteria in the dish. 1.) Express the number of bacteria, P, as a function of t hours passed. Note: Round the growth rate to 4 dec. places. P(t) = 2.) Use the model from part a to determine the number of bacteria, rounded to a whole number, in the dish after 15 hours