The step-by-step solution for your problem is as follows.
8 kg cost 260
1 kg costs 260/8=32.5
Now 32.5 rs needed to buy 1 kg sugar
1 rs needed to buy 1/32.5 kg sugar
so, 788.50 rs needed to buy 788.5*1/32.5= 24.26 kg sugar.
Hope it helps.
All the best!