19. The population of a small new community has \( 200 \) members and obeys the law of uninhibited growth following the formula \( A ( t ) = 200 e ^ { k t } \) ,
a. Find \( k \) if the population grew to \( 432 \) people after \( 7 \) years. (Round \( k \) to \( 2 \) decimal places).(3points)
b. What is the population after \( 20 \) years? (2 points)
c. When will the population reach \( 6000 \) people? [3 points]