We can apply the rule of 3 to solve this.
As he types 90 words in 2 minutes, he will type x words in 7 minutes.
We can calculate x as:
[tex]\begin{gathered} 2\min \longrightarrow90\text{ words} \\ 7\min \longrightarrow x=\frac{90}{2}\cdot7=315\text{ words} \end{gathered}[/tex]Answer: In 7 minutes he will type 315 words.