csat-suneung 2023 Q18

csat-suneung · South-Korea · csat__math 3 marks Arithmetic Sequences and Series Compute Partial Sum of an Arithmetic Sequence

For two sequences $\left\{ a _ { n } \right\}$ and $\left\{ b _ { n } \right\}$, $$\sum _ { k = 1 } ^ { 5 } \left( 3 a _ { k } + 5 \right) = 55 , \quad \sum _ { k = 1 } ^ { 5 } \left( a _ { k } + b _ { k } \right) = 32$$ What is the value of $\sum _ { k = 1 } ^ { 5 } b _ { k }$? [3 points]

For two sequences $\left\{ a _ { n } \right\}$ and $\left\{ b _ { n } \right\}$,
$$\sum _ { k = 1 } ^ { 5 } \left( 3 a _ { k } + 5 \right) = 55 , \quad \sum _ { k = 1 } ^ { 5 } \left( a _ { k } + b _ { k } \right) = 32$$
What is the value of $\sum _ { k = 1 } ^ { 5 } b _ { k }$? [3 points]

Paper Questions

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