AB Ltd's gross sales was $4,200, net sales account for an average 10% discount on all items sold and 5% of items were returned during the year. Also during the year the cost of goods sold was $3,628. Required 1: If beginning and ending inventory are zero (Just in time), AB's net purchases for the perlod must have been: $ Required 2: AB's Sales Returns and Allowances for the period must have been; $ Required 3: AB's Sales Discounts for the period must have been: $ Required 4: AB's Net Sales for the period must have been: $ Required 5: AB's Gross Profit on Sales in dollars for the period must have been (in case of negative, then use "- (minus sign) before the number): $