From 1960 to 1990, the annual percentage increase in the production of CD's was fairly constant. In 1960 production for PopRock company was 40 CD's per year, by 1990 PopRock company was producing 40,000 CD's per year. Model the production with an exponential function P=abt, where t is the number of years since 1960, a is the production of CD's in 1960 and P is the annual production. b=