It should be 8.5 yuan. You can set a diary for X yuan, a pen for Y yuan and a ballpoint pen for Z yuan. Then, according to the meaning of the question:

5x+4y+3z=24.5

3x+4y+5z=43.5

If you want to add the two formulas, you get 8(x+y+z)=68.

Therefore, x+y+z=8.5.

A: ——————

Will it? Please give points if you are satisfied. If you are not satisfied, I will help you answer. Hmm. How interesting