Tommy, Willies, Maggie and Ann bought 20 goodies for 20 cents. The dulce de leche is worth 4 cents a box, 4 chewing gum is worth 1 cent, and two chocolates are worth 1 cent.
What goodies did they buy?
The boys had to buy 3 boxes of dulce de leche at 4 cents each. 15 chocolates for 7.5 cents and 2 chewing gum to complete the missing penny.