A track team has 121people. The ratio of boys to girls is 7:4. How many more boys are there on the team than girls?

Ratio of 7:4  means that 7/11 are boys and 4/11 are girls

7/11(121) - 4/11(121) =  33 more boys than girls

A track team has 121people. The ratio of boys to girls is 7:4.

How many more boys are there on the team than girls?

$\begin{array}{|rcll|} \hline \frac{7}{11} + \frac{4}{11} &=& 1 \quad & | \quad \cdot 121 \\ \frac{7}{11}\cdot 121 + \frac{4}{11}\cdot 121 &=& 121 \\ \frac{7}{11}\cdot 11\cdot 11 + \frac{4}{11}\cdot 11\cdot 11 &=& 121 \\ 7\cdot 11 + 4\cdot 11 &=& 121 \\ \underbrace{77}_{\text{boys}} + \underbrace{44}_{\text{girls}} &=& 121 \\\\ && \text{boys} - \text{girls} \\ &=& 77-44 \\ &=& 33 \\ \hline \end{array}$