Answer
$S_{11}=46.75$
Work Step by Step
We are given:
$\sum_{k=0}^{10}(3+0.25k)$
Since the values go up by 0.25 consistently, we see that this is an arithmetic sequence.
We find the first and last terms of the sequence:
$a_{0}=3+0.25*0=3$
$a_{10}=3+0.25*10=5.5$
Thus the partial sum is:
$S_{11}= \frac{11}{2}(3+5.5)=46.75$