2. If the original price of A is 5 times, then B is 4 times. According to the meaning of the question, the equation can be listed: (5x-20):(4x+20)= 1:8.

When solving the equation, X=5, then the original price of b is 4x=20 yuan.

3. The number of people is different, so the largest distribution in front should be, 2 1 20, 19, 18, so the smallest distribution should be, 12, which means at least 12.

According to the meaning of the question, each triangle is a quarter of the rectangular area, that is, 6×9÷4= 13.5 square centimeters.