Problem: a shopkeeper sold an article at $ 1050 and gained a 20 % profit . what was the cost price ?
Rationale: "let x be the cost price . 1.2 x = 1050 x = 1050 / 1.2 = 875 the answer is e ."
annotated_formula: multiply(const_100.0, divide(const_100, add(1050, 20)))