For any linear change in current from \( I_{\text{initial}} \) to \( I_{\text{final}} \), the total charge can also be calculated using average current:
\( Q = I_{\text{avg}} \times \Delta t = \frac{I_{\text{initial}} + I_{\text{final}}}{2} \times \Delta t \).
In this specific case, \( Q = \frac{10 + 0}{2} \times 4 = 5 \times 4 = 20 \text{ C} \).