Answer: Hello!
If we define S as the price of the screen-print ones, and E as the price of the embroidered jackets, then the total price for 108 of each is:
Screen-print = 108*S
embroidered = 108*E
If you want to know the difference in the prices, you need to do a subtraction of the prices, this is:
108*S - 108*E
now we see that 108 is a common factor, then we can do an "inverse distribution"
108*S - 108*E = 108*(S - E)
then the difference in the prices is the amount of students multiplied by the difference in the prices for each jacket.