Answer:
16 minutes
Explanation:
Given
Represent minutes with M and Phone calls with P.
When M = 8; P = 2
Required
Determine M when P = 4
First, we need to determine the constant of proportion using:

Where k represents the constant:

Divide through by 2


Solving for M, when P = 4
Substitute 4 for P and 4 for k in



Hence:
She spent 16 minutes in total