Chapter 4.5, Problem 11P

JosĂ© is 3 years younger than 3 times his brother’s age. Write a rule that represents JosĂ©’s age $j$ as a function of his brother’s age $b$.

How old is José if his brother is 5?

To determine

To find: age of Jose and write rule which represents Jose’s age j as function of his brother’s age b.

Answer to Problem 11P

12 year old is the age of Jose when his brother is 5 year old.

Explanation of Solution

Given information:

Jose is 3 year younger than 3 times of his brother’s age.

Consider Jose’s age is J and his brother’s age is b.

Write it in mathematically,

  $J=3b-3$

This is the required rule,

Now find the age of Jose if his brother is 5 year old,

  $\begin{array}{l}J=3b-3\\ =3\left(5\right)-3\\ =15-3\\ =12\end{array}$

12 year old is the age of Jose when his brother is 5 year old.