What is the average (arithmetic mean) of a certain series of N consecutive integers?
(1) The sum of the terms of the series is N.
(2) The sum of the greatest and least terms is 2.
How should I solve this question? Thanks for your help!
Arith. Mean of any series of consecutive integers = (a+l)/2 where a= first integer, l= last integer.
=> Sum of that series = (number of terms in the series)*(Average of the series) = N*(a+l)/2
Stmt 1) given, Sum= N => N*(a+l)/2= N => Mean = 1 => Sufficient info
Stmt 2) given, a+l= 2 => (a+l)/2 or the Mean = 1 => Sufficient info
Answer = D