Calculate the number of moles of H2O2 required to produce 0.08 moles of HNO3 by the following reaction.

7 H2O2 + N2H4 2 HNO3 + 8 H2O

clearly, 7 moles H2O2 produce 2 moles HNO3

So, use that ratio to find x:

7/2 = x/.08