Problem: john bought a total of 20 mangoes and oranges . each mango costs 80 cents and each orange costs 60 cents . if the average price of the 20 mangoes and oranges that john originally purchased was 65 cents , then how many oranges needs to return to raise the average price of his purchase to 72 cents ?
Rationale: "let number of mangoes be x , number of oranges be 12 - x 0.80 x + ( 20 - x ) 0.60 / 20 = 0.65 solving for x , we get x = 5 - - > mangoes 5 , oranges 15 now , number of oranges to be returned be y 0.80 * 5 + ( 15 - y ) * 0.60 / 20 - y = 0.72 solving for y , y = 12 ans : e"
annotated_formula: multiply(divide(65, const_100), 20)