回复：请大家解决一道数学题。

This is not a well formulated mathematical problem. First what do you mean by "两个方法同时使用"? Do you mean you take the method of 70% if the results of the two methods do not agree? This is the same as the method of 70%. Second what do you mean 独立? Although the two methods are different, both may use the same data in making prediction.