### Home > MC1 > Chapter 1 > Lesson 1.1.2 > Problem1-15

1-15.

Maria's brother came back with another problem. He said, "If you multiply my number by $\textit{9}$ and add $\textit{4}$ you get $\textit{67}$."

1. What number was he thinking of?

Having trouble? Go back and look at the 1-14, because that problem is very similar to this one.
Remember to pick a reasonable number and use it to do the steps that Maria's brother describes.

$7$

2. Explain how you figured out your answers to Maria's and her brother's number puzzles.

Did you guess and then check whether your guess worked?
Did you work backwards?