at 10, there were 2000.....at 12, there were 2500..
that means in 2 hrs, they increased by 500....that means they increase at a rate of 250 per hr
f(x) = 250h + 2000.....midnight is 12 hrs from 10 a.m....so h = 12
f(12) = 250(12) + 2000
f(12) = 3000 + 2000
f(12) = 5000 <===
