Ineed this is too confusing for me

Which problem is to confusing for me

Let, S = Shirt, J = Jeans

14a) 
This question asks for the discount to be added after everything else.
S= 12   J=19
3S + 2J -3 = Cost with discount applied to total
^ This expression adds to costs, then takes away the $3 discount as the end.

14b)
This questions says the discount is added on every shirt, we get a similar expression:
3(S-3) + 2(J-3) = Cost with discount applied on every shirt and jeans

14c)
The difference between a) and b) is that:
 > the discount in a) is applied on the total, meaning a lower discount
> the discount for b) is applied on each shirt and jeans, meaning a greater discount

14d)
If I were the shop owner I would be more specific of what the discount included, for example we don't know whether to discount each product (shirts and jeans) or only discount the total.

Idon’t know actually is more difficult