Given:
Shirt = $12
Pants = $19
Shirts = 3 * 12 = 36
Jeans = 2 * 19 = 38
Total cost = 36 + 38 = 74
If Pani has a discount of $3 per shirt and $3 per pair of jeans.
Shirts : 3 * (12-3) = 3 * 9 = 27
Jeans : 2 * (19-3) = 2 *16 = 32
Total cost w/ discounts = 27 + 32 = 59
If Pani paid $71, she got a discount of $3 from the total amount of $74. The discount given was from the total sales, not the price of each item.
Sign should state "$3 discount from total purchase".