Whats the tension T' in string 1 if tension of highlighted string is T

[Physics freak]

Homework Statement

I have attached image of question as well as my attempt!

Relevant Equations

If we consider string as uniform then T'=T but if make fbd of pulley 1 the T'-2T-ma1=0 = T'=2T as m=0 for the given pulley. This is contradicting

 

[haruspex]

Though the details are different, this is essentially the same issue as in your https://www.physicsforums.com/threa...ead-to-the-wrong-results.979612/#post-6253449.
Please see my reply there.