Answer
$6I_s$
Work Step by Step
We know that
$\frac{N_p}{N_s}=\frac{I_s}{I_p}$
Now for transformer 1
$\frac{N_{1p}}{N_{1s}}=\frac{I_{1s}}{I_{1p}}$......eq(1)
For transformer 2
$\frac{N_{2p}}{N_{2s}}=\frac{I_{2s}}{I_{2p}}$......eq(2)
Dividing eq(2) by eq(1), we obtain:
$\frac{N_{1p}}{N_{1s}}\frac{N_{2s}}{N_{2p}}=\frac{I_{1s}}{I_{1p}}\frac{I_{2p}}{I_{2s}}$
We substitute $2N_{1p}$ for $N_{2p}$ and $3I_{1p}$ for $I_{2p}$ and $N_{1s}=N_{2s}$
$\implies \frac{N_{1p}}{N_{2s}}\frac{N_{2s}}{2N_{1p}}=\frac{I_{1s}}{I_{1p}}\frac{3I_{1p}}{I_{2s}}$
This simplifies to:
$I_{2s}=6I_{1s}$
