3For2Sale.js

/*
There's a "3 for 2" (or "2+1" if you like) offer on mangoes. For a given quantity and price (per mango), calculate the total cost of the mangoes.

Examples
mango(3, 3) ==> 6    # 2 mangoes for 3 = 6; +1 mango for free
mango(9, 5) ==> 30   # 6 mangoes for 5 = 30; +3 mangoes for free
*/

//Answer//

function mango(q, p){
return (q-Math.floor(q/3))*p
}