Answer:
Step-by-step explanation:
Alright, lets get started.
Suppose A and B , both has initial volume, say x
120 ML is poured from B to A, then new volumes of A and B will be:
new volume of A 
new volume of B 
Volume of B is now four times volume of A, then




So, the initial volume of A and B containers is 200
So, at the end, volume of container A = 
Hence the answer is 80 : Answer
Hope it will help :)