70. 6564-!-item-!-187;#058&004850
If eleven consecutive integers are listed from least to greatest, what is the average (arithmetic mean) of the eleven integers?
(1) The average of the first nine integers is 7.
(2) The average of the last nine integers is 9.
Ans:D
想請教一下 eleven consecutive integers 所以我麼知道 等差=1
是嗎?