Answer
We can estimate that the half-life of the viral load is 3.5 days.
Work Step by Step
On the graph, we can see that the viral load $V = 60$ on about day 3.
The viral load $V = 30$ on about day 7.
The viral load $V = 15$ on about day 10.
The viral load reduces by half every 3 or 4 days.
We can estimate that the half-life of the viral load is 3.5 days.
