College Algebra 7th Edition

$S_{11}=46.75$
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: $S_{11}= \frac{11}{2}(3+5.5)=46.75$