This section is not completed yet, but in the meantime here are some practice questions.

Remember:

In questions involving ratios where you know the total, divide the total by the sum of the ratio numbers, then multiply by the relevant ratio number to find how many in that group, e.g. if a pencilcase contains pens and pencils in the ratio $4$ to $5$, and the total number of pens and pencils is $18$, calculating $18\div(4 + 5) \times 4$ would give the number of pens.