The ratio of 15 to 21 is translated as;
[tex]15\colon21=\frac{15}{21}[/tex]Then, we can reduce the ratio by dividing the numerator and denominator by 3:
[tex]\begin{gathered} \frac{15}{21}=\frac{5}{7} \\ \frac{5}{7}=5\colon7 \end{gathered}[/tex]The ratio of 15 to 21 can be simplified to 5:7
