A 25 watt, 220 volt bulb and a 100 watt, 220 volt bulb are connected in series across 440 volt line

$R=\frac{V^2}{P};V=iR$  their resistances are in the ration 4:1 and in series the potential is directly proportional to resistance so potential of 25 W will be more than 220 V so it will fuse.