Question

Carlos and Franklin are giving away books at a fair. They have 10 boxes, andeach box holds 20 books. On the first day, they gave away 3 3/4 .boxes.On the second day, they gave away 4 2/5 boxes. How many boxes of books dothey have left?

Answer 1

To find how many boxes they have left we need to know how many they gave away. To do that we will add the number of box given on the first day and on the second day.

`\begin{gathered} \text{boxes given}=3(3)/(4)+4(2)/(5) \\ \text{boxes given}=3+(3)/(4)+4+(2)/(5) \\ \text{boxes given}=(3\cdot20+5\cdot3+4\cdot20+2\cdot4)/(20) \\ \text{boxes given}=(60+15+80+8)/(20) \\ \text{boxes given}=(163)/(20) \end{gathered}`

We then subtract the number of boxes they had on the start by the number of box they've given away already. We have:

`\begin{gathered} \text{boxes left}=20-(163)/(20) \\ \text{boxes left}=(20\cdot20-163\cdot1)/(20) \\ \text{boxes left}=(400-163)/(20) \\ \text{boxes left}=(237)/(20)=11(17)/(20) \end{gathered}`

They have 11 17/20 boxes left.