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If ∣m!(m+1)!(m+2)!(m+1)!(m+2)!(m+3)!(m+2)!(m+3)!(m+4)!∣=2k\begin{vmatrix} m! & (m+1)! & (m+2)! \\ (m+1)! & (m+2)! & (m+3)! \\ (m+2)! & (m+3)! & (m+4)! \end{vmatrix} = 2k, where mm is a positive integer then which of the following are factors of kk?

A. m!m!

B. (m+1)!(m+1)!

C. (m+2)!(m+2)!

D. (m+3)!(m+3)!

Choose the correct answer from the options given below:

Solution

✅ Correct Option: 3

Take m!m!, (m+1)!(m+1)! and (m+2)!(m+2)! common from the three rows. The reduced determinant, after row operations R2−R1R_2-R_1 and R3−R1R_3-R_1, evaluates to 22.

So the determinant equals 2 m!(m+1)!(m+2)!2\,m!(m+1)!(m+2)!, giving k=m!(m+1)!(m+2)!k = m!(m+1)!(m+2)!.

Hence m!m!, (m+1)!(m+1)! and (m+2)!(m+2)! are factors, but (m+3)!(m+3)! need not be.

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