Question

How do I go about solving it. What would the answer be?

Answer 1

The given sum is

`\sum ^9_(k\mathop=4)(5k+3)`

This means we have to replace k = 4, 5, 6, 7, 8, 9, and then we sum

`\begin{gathered} (5\cdot4+3)+(5\cdot5+3)+(5\cdot6+3)+(5\cdot7+3)+(5\cdot8+3)+(5\cdot9+3) \\ 20+3+25+3+30+3+35+3+40+3+45+3=213 \\ \end{gathered}`

Hence, the sum is equal to 213. The right answer is C.