Bert, Ernie, and Peggy collect stamps.  Bert has four times as many stamps as Ernie, but Ernie has three times as many stamps as Peggy.  If Peggy currently has 75 stamps in her collection, how many stamps does she need to add to her collection to have a collection as large as Bert's collection?
Ernie has three times as many stamps as Peggy, or 3*75=<<3*75=225>>225 stamps.
Bert has 4 times as many stamps as Ernie, or 4*225=<<4*225=900>>900 stamps.
Thus, Peggy would need 900-75=<<900-75=825>>825 more stamps to have a collection as large as Bert's.
#### 825