Question

A bottle of ant killer holds 1 L of concentrate. To make up a solution, 5 capfuls are added to 1, 5 L of water. Each capful is 25 mL. How many litres of solutions can be made if you use the entire bottle of concentrate?

Answer 1

So first we have 1.5L of water and we add 5 25mL capfuls of ant killer. First we should work with the same unit so we transform liters into mililiters using the rule of three:

`\begin{gathered} 1L\rightarrow1000mL \\ 1.5L\rightarrow x \end{gathered}`

Where:

`x=(1.5L\cdot1000mL)/(1L)=1500mL`

So we know that we have 1500mL of water. The total amount of ant killer that was added to this water is:

`5\cdot25mL=125mL`

Then the solution has 1500mL of water and 125mL of ant killer which means that the total volume of solution is:

`1500mL+125mL=1625mL`

Knowing this, we need to find how many liters of solution we can make if we use the entire liter of ant killer. The information we have is that with 125 mL of ant killer you can make 1625 mL of solution. If we use the rule of three:

`\begin{gathered} 125mL\text{ of ant killer}\rightarrow1625mL\text{ of solution} \\ 1000mL\text{ of ant killer}\rightarrow x\text{ of solution} \end{gathered}`

Where x is the amount of mililiters that we are looking for and is given by:

`x=(1000mL\cdot1625mL)/(125mL)=13000mL`

So we can make 13000 mL of solution but we must express it in litres:

`\begin{gathered} 1000mL\rightarrow1L \\ 13000mL\rightarrow x \end{gathered}`

With:

`x=(13000mL\cdot1L)/(1000L)=13L`

Then the answer is that you can make 13 L of solution with the entire bottle of concentrate.