David works at a science lab that conducts experiments on bacteria. The population of the bacteria multiplies at a constant rate, and his job is to notate the population of a certain group of bacteria each hour. At 1 p.m. on a certain day, he noted that the population was 500 and then he left the lab. He returned in time to take a reading at 4 p.m., by which point the population had grown to 13,500. Now he has to fill in the missing data for 2 p.m. and 3 p.m. What was the population at 3 p.m.?	Pick
A) 6500
B) 3500
C) 2500
D) 4500
E) 2000
let the rate be x, then population of the bacteria after each hour can be given as 500,500x, 500(x^2), 500(x^3)   now population at 4pm =13,500   thus we have 500(x^3) = 13,500 =27   thus x=3   therefore population at 3pm = 500(9) = 4,500   Answer : 4500
<result>D</result>
David works at a science lab that conducts experiments on bacteria. The population of the bacteria multiplies at a constant rate, and his job is to notate the population of a certain group of bacteria each hour. At 1 p.m. on a certain day, he noted that the population was 500 and then he left the lab. He returned in time to take a reading at 4 p.m., by which point the population had grown to 13,500. Now he has to fill in the missing data for 2 p.m. and 3 p.m. What was the population at 3 p.m.?