一道GMAT数学题……求解……

问题描述:

一道GMAT数学题……求解……
Ifthe average (arithmetic mean) of six numbers is 75,
how many of the numbers are equal to 75
(1) None of the six numbers is less than 75.
(2) None of the six numbers is greater than 75.

6个数的算术平均=75 => 应有>75者也有 6个都是75