Analysing circuits question
Just practicing my \$\LaTeX\$ stuff....

R2 || R3 = \$\dfrac{1}{\frac{1}{20}+ \frac{1}{30}}\$ = 12 ohm.

Hence total resistance seen by 9V supply is 12 ohm + 6 ohm = 18 ohm hence current = 0.5 A.

The rest is just ohms law.