Problem: the wages earned by robin is 40 % more than that earned by erica . the wages earned by charles is 60 % more than that earned by erica . how much % is the wages earned by charles more than that earned by robin ?
Rationale: "explanatory answer let the wages earned by erica be $ 100 then , wages earned by robin and charles will be $ 140 and $ 160 respectively . charles earns $ 40 more than robin who earns $ 140 . therefore , charles ' wage is 40 / 140 * 100 = 28.57 % . the correct choice is ( c )"
annotated_formula: multiply(divide(subtract(add(const_100, 60), add(const_100, 40)), add(const_100, 40)), const_100)