Two weight mean XXX of is intere A and B,,,,wight is v and w,,,,fomulate is (v+w)/(v/A+w/B)..,and the weight is 10 and 20,,,what the Two weight mean when 10 is twice of 20.

• 题目不是很全，但在第二题，看了我半天没看明白，后来有点大彻大悟，算出是12，也不知道是否对，大牛更正。