The area of the two designs are given as 52 square inches and 61.375 square inches.
In these the second design 61.375 square inches is having the greater area.
If 500 envelops are made then area of paper = 61.375x500 =30687.5 square inches.
If envelops having 52 square inches are made out of 30687.5 square inches of paper ,number of envelops made =30687.5 ÷ 52=590.144
590 small envelops can be made having area as 52 square inches.
It is 590-500=90 more than the larger envelops made.