Question

suppose a population of 250 crickets doubles in size every six months. How many crickets will there be after two years?

Answer 1

double every 6 months 

in 6 months there would be 250*2 = 500 crickets

 in 1 year there would be 500*2 = 1000 crickets

in 1.5 years there would be 1000 *2 = 2000 crickets

 in 2 years there would be 2000 *2 = 4000 crickets