25 mL of a mixed solution of sodium carbonate and sodium bicarbonate required 10 mL of `N//20` HCl when titrated in the presence of phenolphthalein but 25 mL of the same when titrated separately in presence of methyl orange required 25 mL of `N//10` HCl. Calculate the amount of anhydrous sodium carbonate and bicarbonate in grams per litre of the solution.
