Miles is 3 years old and because his grandparents love to spoil him, they have given him money to spend at the toy store as a birthday present.
Miles utility will increase by 100 units if he purchases a new set of Legos and it will cost him $50. Mile's second favorite thing to play with are firetrucks,. Firetrucks cost $20 and each new firetruck improves his utility by 80 units. Mile's third favorite toy are trains. Trains improve his utility by 15 units nd cost $5 each.
Miles doesn't have spend all of his money at once, but wants to get as much happiness as possible from his money.
If Mile's buys only one toy, which should he buy to maximize his utility?