EAMCET Engineering 2003 Solved Paper

Consider the following reaction equilibrium:
N2(g)+3H2(g)⇌2NH3(g)
Initially, 1 mole of N2 and 3 moles of H2 are taken in a 2 L flask. At equilibrium state if, the number of moles of N2 is 0.6 , what is the total number of moles of all gases present in the flask?