Answer :
[tex]7x-number\ of\ girls\\4x-number\ of\ boys\\\\7x+4x=77\\11x=77\ \ \ \ \ \ |:11\\x=7\\\\7\cdot7=49\\\\There\ are\ 49\ girls[/tex]
x - the number of girls
y - the number of boys
[tex]x:y=7:4 \\ \frac{x}{y}=\frac{7}{4} \\ 7y=4x \\ y=\frac{4}{7}x[/tex]
The total number of students is 77.
[tex]x+y=77 \\ x+\frac{4}{7}x=77 \\ \frac{7}{7}x+\frac{4}{7}x=77 \\ \frac{11}{7}x=77 \\ x=77 \times \frac{7}{11} \\ x=7 \times 7 \\ x=49[/tex]
There are 49 girls in the student council.
y - the number of boys
[tex]x:y=7:4 \\ \frac{x}{y}=\frac{7}{4} \\ 7y=4x \\ y=\frac{4}{7}x[/tex]
The total number of students is 77.
[tex]x+y=77 \\ x+\frac{4}{7}x=77 \\ \frac{7}{7}x+\frac{4}{7}x=77 \\ \frac{11}{7}x=77 \\ x=77 \times \frac{7}{11} \\ x=7 \times 7 \\ x=49[/tex]
There are 49 girls in the student council.
