Question on profit and loss

Question

Ans.600

My attempt:

CP1=100x

SP1=120x

CP2=100x-100

SP2=120x-100

P2=124% of (CP2)

=>20x=$\frac{124}{100} $(100x-100)

x=$\frac{124}{104}$*100

The answer is nowhere close.

Answer 1

It will be $$20x=\dfrac{(20+4)(100x-100)}{100}$$

and actually $$120x-100=\dfrac{124(100x-100)}{100}$$