csat-suneung 2026 Q2

csat-suneung · South-Korea · csat__math 3 marks Arithmetic Sequences and Series Compute Partial Sum of an Arithmetic Sequence
For the sequence $\left\{ a _ { n } \right\}$, when $\sum _ { k = 1 } ^ { 4 } \left( 2 a _ { k } - k \right) = 0$, what is the value of $\sum _ { k = 1 } ^ { 4 } a _ { k }$? [3 points]
(1) 1
(2) 2
(3) 3
(4) 4
(5) 5
For the sequence $\left\{ a _ { n } \right\}$, when $\sum _ { k = 1 } ^ { 4 } \left( 2 a _ { k } - k \right) = 0$, what is the value of $\sum _ { k = 1 } ^ { 4 } a _ { k }$? [3 points]\\
(1) 1\\
(2) 2\\
(3) 3\\
(4) 4\\
(5) 5