OG上的一道！

gzzxl

If the 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.

麻烦讲讲这题是啥意思，没能读懂啊！~谢谢了@-@