A balanced wheatstone bridge is shown the values of currents $i_{1 }$and$i_{2 }$are (ATB)

Since it is a balanced Wheatstone bridge, current through galvanometer is zero.

resistances 2ohm and 4ohm are in series and so are 3ohm and 6 ohm

Therefore, effectively 6ohms and 9ohms resistances are in parallel.

Currents i₁ and i₂ are in the ratio 9 : 6. 

Effective resistance of the bridge is 

${\mathrm{R}}_{\mathrm{eff}}=\frac{9\times 6}{9+6}=3.6\mathrm{ohm}$

Current i in circuit is

$i = \frac{6}{3.6+0.4}=1.5A$

$\therefore i_1 = \frac{3i}{5}=0.9A$

$\therefore i_2 = \frac{2i}{5}=0.6A$