Total weight of 3 boxes is $$60\frac{1}{2}$$ Kg. $$2^{nd}$$ box weighs $$3\frac{1}{2}$$ Kg more than 1st box. The 3rd box weighs $$2\frac{1}{2}$$ Kg more than 2nd box. The
weight of 1st box is:

A

36 kg

B

17 kg

C

18 kg

D

None of these