Tina is putting together party bags for her little brother’s birthday. She needs 15 party bags that are all the same, made up from balloons, small toys and sweets. She can buy bags of 20 balloons, bags of 9 toys and bags of 40 small packets of sweets. She doesn’t mind if she has sweets left over, but doesn’t want any balloons or toys left over. What is the smallest number of each that she has to buy?