1969 AMC 12 Problem 9

Attempt Problem 9 of the 1969 AMC 12 below, then check your answer against the professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 1969 AMC 12 solutions, or check the answer key.

All problems are used with official legal permission of the Mathematical Association of America (MAA).

The arithmetic mean (ordinary average) of the fifty-two successive positive integers beginning with

2

is:

27

27\dfrac14

27\dfrac12

28

28\dfrac12

Find the fifty-second integer in the list

The mean of an arithmetic sequence is the average of its first and last terms

The integers run from

2

through

2+51=53.

Their mean is the average of the first and last:

\frac{2+53}{2}=\frac{55}{2}=27\frac12.

Therefore, the correct answer is C.

Problem 9 in other years