Answer:
The box alone weighs 6 kg
Explanation:
Let, weight of Apple be x, Oranges be y, Guavas be z nd box a.
A box of Apple weighs 270kg and 500g i.e270.5kg
a+x =270.5---(1)
A box of oranges weighs 192.5kg
a+y=192.5---(2)
A box of guavas weighs 245
a+z=245---(3)
Fruits together weigh 690 kg
x+y+z=690---(4)
Combining (1),(2),(3), we get
3a+x+y+z=708---(5)
From 4&5
3a+690=708
3a=18
a=6
So the box weighs 6 kg