You ask: The grocery store uses toffee and chocolate as gift candy. The mass ratio of toffee to chocolate in each box is 5: 3. If there are 60 kilograms of toffee and 60 kilograms of chocolate, how many kilograms of chocolate will be left when the toffee is used up? How many kilograms of toffee can you finish?

Reading the topic, we can find that the amount of toffee used to make this gift candy is a little too much, so let's see how much chocolate is needed for 60 kilograms of toffee. 60×3/5=36, that is, the toffee is used up, and the chocolate is 60-36=24 kg. Then we'll see how much toffee is needed for 24 kilograms of chocolate. 24×5/3=40, that is to say, 40 kilograms of toffee can use up all the chocolate.