Answer: The required ratio is 3 : 1.
Step-by-step explanation: Given that Juanita is 15 years old and her brother is 5 years old.
We are to find the ratio of Juanita's age to her brother's age.
Let x and y represents the ages of Juanita and her brother respectively in years.
Then, according to the given information, we have
[tex]x=15,\\\\y=5.[/tex]
Therefore, the ratio of Juanita's age to her brother's age is given by
[tex]x:y\\\\=\dfrac{x}{y}\\\\\\=\dfrac{15}{5}\\\\\\=\dfrac{3}{1}\\\\=3:1.[/tex]
Thus, the required ratio is 3 : 1.