Melvin pays for 4 brownies and 3 cookies. Lily spends twice as much paying for 2 brownies and 16 cookies. A brownie is how many times as expensive as a cookie?
Let x be the cost of a brownie and y the cost of a cookie. The amount of money Melvin spends is 4x+3y. The amount of money Lily spends is 2x+16y, which is double of 4x+3y(the amount of money Melvin spent). We then form an equation.
Therefore a brownie is 5/3 times as expensive as a cookie.