we know that
Ratio is the quantitative relation between two numbers
so
Let
x-------> number of boys in the class
y-------> number of girls in the class
[tex]ratio=\frac{x}{y}[/tex]
in this problem we have
[tex]x=6\ boys\\y=15\ girls[/tex]
Find the ratio
substitute the values in the formula
[tex]ratio=\frac{6}{15}[/tex]
Divide by [tex]3[/tex] both numerator and denominator
[tex]ratio=\frac{2}{5}[/tex]
therefore
the answer is
the ratio of boys to girls is [tex]\frac{2}{5}[/tex]
