If you take 3 grams of P in a nail bottle, it is equivalent to taking 5 grams of Q,

Bottle B contains 6-3x grams, Q 12-7x grams, (6-3X):( 12-7x)=3/7, so x= 1.

So I took a bottle of 3x = 5x = 8g.

Let one side be A, the other side be 2a, and the third side be c-3a. Because the sum of the two sides is greater than the third side, the difference between the two sides is smaller than the third side.

3a & gtc-3a，c-2a & gt； 2a，get:c/4 >； a & gtc/6

There is obviously one.

The range of a is c/6.