Ans: D

given expression looks a bit ... you know what i mean: so lets make it easy lets say that first number in ! is x so expression will become

\((x!)((x+1)! + x!)\) from here.. let me also write !x as F(x)

If we take the F(x) inside, expression will become [F(x)*F(x+1) + F(x)^2]

We know F(x+1) = (x+1)*F(x)

so it becomes [F(x)^2 * (x+1) + F(x)^2]

npw take F(x)^2 common Expression will become = F(x)^2 [x+1+1]

F(x)^2 [x+2]

now we need to know if this is whole square or not. We know F(x)^2 is always so we just need to know if (x+2) is whole square or not.

Put x =23 , we know 25 is a whole square so D is the ans.

Bunuel wrote:

Which of the following numbers is a perfect square?

A. \((20!)(21! + 20!)\)

B. \((21!)(22! + 21!)\)

C. \((22!)(23! + 22!)\)

D. \((23!)(24! + 23!)\)

E. \((24!)(25! + 24!)\)

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