GWD 01-21

[Emilyh]

The results of a certain experiment included 6 data values that were all multiples of the same number c, namely, c, 8c, 2c, 5c, 4c, and 4c. Was the average (arithmetic mean) of the 6 data values greater than 8?
(1) c < 4
(2) c > 2

Ans:B

請問要如何判斷呢?

謝謝

[Ace]

六數平均為4c
條件A C<4 如果C=0則小於8 如果C=3則大於8 故不充分
條件B C>2 所以4C>8 充份