Let the total workload be 1, the work efficiency of A be1/x ... and the work efficiency of B be 1/(x+5).

The equation can be listed as:1[(1/x)+1/(x+5)] = 6.

Solution, x= 10, or x=-3 (truncation)

Therefore, it takes 10 days for Party A to work alone, and 15 days for Party B to work alone.

2. If there are X students in this class, the retail price is M/x (because: each student just runs out of M yuan to buy photo albums).

List the equations: (m/2-2) (x+12) = m.

X 2+ 12x-6m = 0.

Because: x; 50, so 38

After substituting one by one, it is found that when x=M/9=54- 12=42, the value range of x is satisfied, and when x = m/8 = 48- 12 = 36.

Therefore, x=42, M=9x=378, and M/x=9.

That is, there are 42 students in this class, and the retail price of each album is 9 yuan.

I hope it's the answer you want, remember to give points ~