Can you help me with this Chemistry Problem?

Question

CH4 flows into a catalytic converter at 25.0atm and 300 degrees celsius at a rate of 1000 L/min. Hydrogen flows into the reactor at 25.0atm and 300°C at 1500 L/min

If 15.0 kg of C2H6 is collected, what is the percent yield of the reaction

Answer 1

2CH4(g) ===> H2(g) + C2H6(g)

It seems that the yield of C2H6 will depend also on the time allowed for reaction. Since CH4 flows at 1000 L/min, the number of minutes that it flows will influence the theoretical yield.  Also, H2 is a product of the reaction, so not sure why it is being added.  Are there any other details the you may have omitted?