A 19.6 g of a given gaseous sample contains 2.8 g of molecules d=0.75 g L−1 11.2 g of molecules (d=3g L−1) and 5.6 g of molecules (d=1.5 g L−1). All density measurements are made at STP. Calculate the total number of molecules (N) present in the given sample. Report your answer in N×1023.
Assume Avogardro's number as 6×1023.