Wheatstone Bridge Questions

Three resistances $P,Q,R$ each of $2\Omega$ and an unknown resistance $S$ form the four arms of a Wheatstone’s bridge circuit. When a resistance of $6\Omega$ is connected in parallel to $S$ the bridge gets balanced. What is the value of $S$?

The resistances of the four arms $P,Q,R,S$ in a Wheatstone bridge are $10\Omega ,30\Omega ,30\Omega ,90\Omega$ respectively. The e.m.f. is $7\text{V}$ and internal resistance is $5\Omega$. What is the current drawn from the cell?