Praise calligraphy

Solution: (1) If the unit price of a pen is X yuan, then the unit price of a brush is (x +4) yuan. From the meaning of the title: 30 x +45( x +4)= 1755, the unit price of a pen is x =2 1 = 25. The unit price of a pen is. The unit price of the brush is 25 yuan. (2) Let a pen with a unit price of 2 1 yuan be Y, and a brush with a unit price of 25 yuan be (105-y). According to the meaning of the question, it is 21y+25 (105-y) = 2447. The solution is: y =