MathDB
Arithmetic Progression

Source:

January 11, 2009
arithmetic sequence

Problem Statement

For every n n the sum of n n terms of an arithmetic progression is 2n \plus{} 3n^2. The r rth term is: (A)\ 3r^2 \qquad (B)\ 3r^2 \plus{} 2r \qquad (C)\ 6r \minus{} 1 \qquad (D)\ 5r \plus{} 5 \qquad (E)\ 6r \plus{} 2 \qquad