Answer:
See Explanation
Step-by-step explanation:
The question is incomplete, as the number line is not given. The general explanation is as follows;
First, record the time she hung up (say, time = x)
To rewind 15 minutes back means, x - 15
So, point on the number line will be x - 15
Take for instance
[tex]x = 45[/tex]
The point on the number line will be:
[tex]x - 15 = 45 - 15[/tex]
[tex]x - 15 = 30[/tex]
See attachment for illustration