the population of a town is 30000 . it decreases annually at the rate of 20 % p . a . what will be its population after 2 years ?
"30000 × 80 / 100 × 80 / 100 = 19200 answer ; b"
subtract(subtract(30000, multiply(30000, divide(20, const_100))), multiply(subtract(30000, multiply(30000, divide(20, const_100))), divide(20, const_100)))