Answer:
a) 35, b) 25, c) 60
Step-by-step explanation:
The number of girls is 10 more than the number of boys, so it's a good thing to choose a variable to represent the number of boys.
Number of boys: b
Number of girls: b + 10
Ratio of girls:boys is 7:5, so
[tex]\frac{b+10}{b}=\frac{7}{5}[/tex]
"Cross multiply" to get
[tex]7b=5(b+10)\\7b=5b+50\\2b=50\\b=25[/tex]
There are 25 boys. There are 10 more girls, so the number of girls is 35, and the total number of students is 60.
That's a packed classroom!
