Which Acceleration Formula is Correct for the Larger Block in the Pulley System?

[dk_ch]

the acceleration of the larger block of mass M on frictionless floor of the pully system as in (fig given bmp attachment) will be
(i) 4mg/(M+17m) (ii) 4mg/(M+16m)

which answer is correct and how?

 

[cristo]

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[dk_ch]

I tried to solve the problem using following two equations taking large and small block
respectively as freebodies

Ma = 4T ------(1)
mg-T = 4ma -------(2)

solving these two i get acceleration of the larger block a = 4mg/(M + 16m)

the answer given in the text is the other one. please provide me the right answer.

 

[PhanthomJay]

I agree with your answer.