2.1. Eighty five per cent of the people who received invitations to a party in the post sent acceptance letters. Two of the invitations sent out by post were incorrectly addressed and not received. Of the people who responded with acceptance letters, one foolishly forgot the date, another made a late excuse by text but arranged for someone else to go in their place and four others, when the day came, found themselves laid up with colds and unable to go. Three of the guests who attended the party were invited personally by the host and sent no written acceptance letters. Forty-five people were invited to the party. How many attended it?​