A man sits on a chair supported by arope passing over a frictionless fixed pulley. The man who weights 1000N exerts a force of 450N on the chair downwards, while pulling on the rope. If the chair weights 250N and g is 10m/s square, then the accerelation of the chair is,

please tell me its answer

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Hint to get you started - draw a free-body diagram of the man.