if annual decrease in the population of a town is 10 % and the present number of people is 500 what will the population be in 1 year ?
"population in 1 year = 500 ( 1 - 10 / 100 ) = 500 * 90 / 100 = 450 answer is a"
multiply(power(divide(subtract(const_100, 10), const_100), 1), 500)