Question 1122538
<pre>
Look at the question first to see what the unknown is:
</pre>
How old is Norma now?
<pre>
Morma's age = N
</pre>
Mark is 16 years old.
<pre>
Mark's age = 16
</pre>
In 4 years he will be twice Norma’s age. 
<pre>
Mark's age in 4 years = 16+4 = 20
Norma's age in 4 years = N+4

Look at this sentence again:
</pre>
In 4 years he will be twice Norma’s age.
<pre>
20 = 2(N+4)

You finish.

Edwin</pre>