As please help

Sodium carbonate forms a number of hydrates of general formula Na2CO3.xH2O*A 3.01 g sample of one of these hydrates was dissolved in water and the solution made up to 250 cm3.*In a titration, a 25.0 cm3 portion of this solution required 24.3 cm3 of 0.200 mol–1 dm–3 hydrochloric acid for complete reaction.*The equation for this reaction is shown below.*Na2CO3 + 2HCl  2NaCl + H2O + CO2*(i)Calculate the number of moles of HCl in 24.3 cm3 of 0.200 mol dm–3 hydrochloric acid.*


ii)Deduce the number of moles of Na2CO3 in 25.0 cm3 of the Na2CO3 solution.*...........………………………………………………………………………….*(iii)Hence deduce the number of moles of Na2CO3 in the original 250 cm3 of solution.*...........………………………………………………………………………….*(iv)Calculate the Mr of the hydrated sodium carbonate.*

Please I need help for iv I have the answer for ii, iii.