Film screening ratio

162 school pupils took part in the film performance, and the ratio of the number of boys to the number of girls was 7:11. Three boys and four girls left during the screening. Then what was the ratio of the number of boys to the number of girls? Adjust the aspect ratio to the base face.

Final Answer:

r₂ =  12:19

Step-by-step explanation:

$$\begin{gathered} n=162 \\ {r}_1=7:11 \\ a=\frac{7}{7+11}\cdot n=\frac{7}{7+11}\cdot 162=63 \\ b=\frac{11}{7+11}\cdot n=\frac{11}{7+11}\cdot 162=99 \\ A=a-3=63-3=60 \\ B=b-4=99-4=95 \\ {r}_2=\frac{A}{B}=\frac{60}{95}=\frac{12}{19}\approx 0.6316=12:19 \end{gathered}$$

Try another example