In MCR

Molar ratios - Number of moles of 1st reactant needed to react with 2nd reactant

For reactants

1:1 implies A + B --> C + D

1:2 E + 2F --> G + H

1:3 I + 3J --> K + L

In reaction if 0.3 mole of 1st reactant is taken 

For 1:1 

take both reactant (1st & 2nd) 0.3 mole

For 1:2

Take 1 st reactant 0.3 mole 

2nd reactant 0.6 mole

This message is a guess for question answered at first sight,

hopefully i am correct, as 

Avogadro number come in to picture while the reaction is initiated with every molecule of 1st and 2nd reactant

So moles should be in proportion, while considering the reaction.

I don't have a reference!

But it might be available in journal of chemical education or vogel's practical book

Thanks prabhakar, Long ago I posted this question what you suggested was the expected answer.