[問題]天山 09-26

[GMAT]

(n-x)+(x-y)+(n-x)+(x-k) what is the value of the expression above?
(1) The average(arithmetic mean) of x,y,c, and k is n.
(2) x,y,c and k are consecutive integers.

答案:A

我選E，為啥條件(1)會成立?

[clbb]

因為你題目看錯了

題目是(n-x)+(n-y)+(n-c)+(n-k)