Question

Missy has three times as many books as Justin Justin has two fewer books in Andrew together they have 17 books how many books does Justin have

Answer 1

$\bf \begin{cases} m=\textit{Missy's amount of books}\\ j=\textit{Justin's amount of books}\\ a=\textit{Andrew's amount of books} \end{cases}\\\\ -----------------------------\\\\ \textit{we know "m" is three times as much as "j"}\implies m=3j \\\\\\ \textit{we also know, "j" is two fewer than "a"}\implies j=a-2 \\\\\\ \textit{their sum is 17}\implies m+a+j=17\\\\ -----------------------------\\\\ \begin{cases} m=3j\\ j=a-2\implies j+2=a\\ ----------\\ m+a+j=17\\ (3j)+(j+2)+j=17 \end{cases}$

solve for "j"