请问新jj一题

to the number 50，60and 70, weights arithmetic mean as w1, w2 and w3, the sum of them is 1, the mean is less than 60, which of the following is true?

THANKS A BUNCH!

设50有a个，60有b个，70有c个

w1＝a/(a+b+c)  w2=b/(a+b+c) w3=c/(a+b+c)

因为mean小于60，因此a>c,  推出w1>w3

不知道说清楚没有，楼上可以查查加权的概念。

权重的概念，觉得正确的只有w₁> w₃

_{愿意听听NN的意见}