Problem: the population of a town is 8000 . it decreases annually at the rate of 20 % p . a . what will be its population after 3 years ?
Rationale: "formula : ( after = 100 denominator ago = 100 numerator ) 8000 ã — 80 / 100 ã — 80 / 100 x 80 / 100 = 4096 answer : b"
annotated_formula: subtract(subtract(8000, multiply(8000, divide(20, const_100))), multiply(subtract(8000, multiply(8000, divide(20, const_100))), divide(20, const_100)))