Let the unit price of "standard" be X yuan, then the unit price of "explanation" is (x+2 1) yuan.

108x=756x+2 1，

Solution: x=3.5,

It is verified that x=3.5 is the solution of the original fractional equation.

Then 3.5+2 1=24.5 (yuan),

A: The standard unit price is 3.5 yuan, and the explanation unit price is 24.5 yuan.