Pls suggest me d right one.....

D question s Consider the following data pertaining to R ltd. for the month of June 2011 Opening stock - 30,000 Closing stock - 40,000 Purchases - 5,60,000 Return outwards - 15,000 Return inward - 20,000 Carriage inward - 5,000 If the gross profit is 20% of net sales , the gross sales for the month of June 2011 is what........????/ Ist approach : Opening stock + purchases + carriage inward - return outward - closing stock = 5,40,000.....which I considered it as 80% of sales.....den for 100% we should calculate it as 5,40,000/.8 = 6,75,000.....!!!! Then with this amt add the net sales , then we get 6,95,000 as gross sales ......!!!! IInd approach : Opening stock + purchases + carriage inward - return outward - closing stock = 5,40,000...then nw less less 20% from return inward....so tat we can get the cost of goods returned .......!!!! So add this to 5,40,000 i.e 5,40,000+16,000=5,56,000......!!!! Then nw 5,56,000/.8 = 6,95,000.....!!!!! Nw plzzz suggest me which one is right approach .......?????