The first piece of the function, \( f(x) = 2.5x \), is defined for the interval \( 0 \leq x \leq 20 \). To find the last point graphed on this segment, we need to evaluate the function at the upper limit of this interval, which is \( x = 20 \).
Calculating \( f(20) \):
\[ f(20) = 2.5 \times 20 = 50 \]
Thus, the last point on the first piece of the function is \( (20, 50) \).
The correct response is:
(20, 50)