MathDB

Give a geometric series

(a_n)

with common ratio of

q

, let

b_1=a_1+a_2+a_3,b_2=a_4+a_5+a_6,\cdots,b_n=a_{3n}+a_{3n+1}+a_{3n+2}

, then sequence

(b_n)

\text{(A)}

is an arithmetic sequence

\text{(B)}

is a geometric series with common ratio of

q

\text{(C)}

is a geometric series with common ratio of

q^3

\text{(D)}

is neither an arithmetic sequence nor a geometric series

Problem Statement