Can anyone explain plz

ali (Student CA CPT ) (130 Points)

06 July 2014  
Goods sent on consignment for Rs.50,000. During transit 1/10th of goods were destroyed by fire. Again 1/9th of goods received by consignee were destroyed by fire in godown. Half of the original goods were sold for Rs.30,000. Freight & insurance paid by consignor Rs.2,500 and Rs.1500 respectively. Calculate closing Stock.

a) Rs.24,000 b) Rs.21,600 c) Rs.20,000 d) Rs.16,200

the answer is 16,200. Can anyone tel me how the answer is 16,200 ???