We are given a graph of the function f(x)
Where input x is the time in hours and the output is the number of boxes packed.
We are asked to find f(1)
f(1) is the output (number of boxes packed) when we substitute the input (x = 1)
Refer to the graph below
As you can see, at time x = 1 the output is 6 (number of boxes packed)
Therefore, f(1) = 6