MathDB

20

Part of 1965 AMC 12/AHSME

Problems(1)

Arithmetic Progression

Source:

1/11/2009
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
arithmetic sequence