A single-phase, $\text{4 kVA}$, $200\: V/100 \: V$, $50 \: Hz$ transformer with laminated $\text{CRGO}$ steel core has rated no-load loss of $450 \: W$. When the high-voltage winding is excited with $160 \: V$, $40 \: Hz$ sinusoidal ac supply, the no-load losses are found to be $320 \: W$. When the high-voltage winding of the same transformer is supplied from a $100 \: V$, $\text{25 Hz}$ sinusoidal ac source, the no-load losses will be _____________________$\text{W}$ (rounded off to $2$ decimal places).
