There are ***92 students in two schools, and the number of students in School A is more than that in School B, then the number of students in School A is ≥47, and the number of students in School B is ≤45.

Let the number of people in B be x, and let the equation be:

60x+50*(92-x)=5020

X=42 There are 42 students in School B and 50 students in School A..

(1) If two schools jointly buy clothes, they have to pay 92*40=3680, which can save 5020-3680= 1340 yuan.

(2) Suppose there are 47 people in A and 45 people in B, and they have to pay 47 * 50+45 * 60 = 5050 > 5020 for clothes, that is to say, the number of people in A is more than 47, and the number of people in B is less than 45 (5050-5020)/(60-50).

(3) If the students from A school 12 are transferred to the calligraphy and painting contest and cannot participate in the performance, then the number of students from A school is 50- 12 = 38, and the students from both schools are 80 * * *, and 80 sets are purchased together. Payable: 80 * 50 = 4,000 yuan > 3,680 yuan.

The most economical clothing purchase scheme is to jointly purchase 9 1 set, and the payable: 9 1 * 40 = 3640 yuan.