AIEEE 2004 Physics Solved Paper

Pressure inside the bubble, P=p0+‌

4T

R

So P∝‌

1

R

where R is the radius of the bubble. It means pressure inside a smaller bubble is greater than the inside of a bigger bubble.
So when two bubbles are connected by a tube, air will flow from smaller bubble to bigger bubble and the size of bigger bubble will increase.