Question

Gregory was p years of age 4 years ago. In terms of p, how old will he be in 4 years from now?

Answer 1

Let us say that Gregory is q years old now. 4 years ago he was (q - 4) years. Using the information of the problem, we formulate the equation:

$\begin{gathered} p=q-4 \\ \Rightarrow q=p+4 \end{gathered}$

After 4 years, he will be (q + 4) years old. Using the previous equation:

$\begin{gathered} q+4=p+4+4 \\ \Rightarrow(q+4)=p+8 \end{gathered}$

Gregory will be (p + 8) years old 4 years from now.