The Red Devils bolstered their attacking options with the loan move for Falcao from Monaco on deadline day.
However, Scholes feels that despite the Colombian's talent it will be impossible to fit him into a side with Rooney and Van Persie, leaving Van Gaal with a tough decision to make.
He wrote in his column in The Independent: "When I watched Falcao play for Porto, Atletico Madrid and Monaco I saw a striker with excellent movement and a goalscoring record that is simply out of this world.
"Falcao creates competition in United's forward line. There is no way that Van Gaal can play Rooney, Van Persie and Falcao together. It will have to be two from three and which two it is hard to say as yet."