80x+60 (100-x) ≤ 7 500, and the solution is: x≤75.
You can buy up to 75 clothes.
(2) Let the total profit be W yuan, because there are not less than 65 pieces of Class A clothing, so 65≤x≤75.
w =( 120-80-a)x+(90-60)( 100-x)=( 10-a)x+3 000。
Scheme 1: when 0 0, w increases with the increase of x,
Therefore, when X = 75 and w has the maximum value, 75 pieces of A clothing and 25 pieces of B clothing can be purchased to obtain the maximum profit;
Scheme 2: When a = 10, all schemes have the same profit, and you can purchase goods according to any scheme;
Option 3: When 10
Therefore, when X = 65 and W has the maximum value, you can buy 65 pieces of A clothes and 35 pieces of B clothes to get the maximum profit.