The ratio of number of moles of sulphuric acid: sodium hyroxide is 1 : 2 respectively. Using this ratio you can find the number of moles of sulphuric acid. 1 mole of sulphuric acid reacts with 2 moles of sodium hyroxide. So dividing the number of moles of sodium hydroxide by 2 gives you the number of moles of sulphuric acid. That gives the same thing he got. Hope that helps :)
