Question

What is the size of the nucleus of Halley’s Comet ?

Answer 1

(8 x 4 x 4) x 2 = (8 x 16) x 2 = 128 x 2 = 256km(approx)

Answer 2

Halley's comet's nucleus  would be composed of a mixture of volatile ices  such as water, carbon dioxide and ammonia and dust it is according to to the theory of Fred Whipple's dirty snow ball model.
The size of the nucleus of Comet Halley will be 1024 km nearly. It is a peanut  or a potato shaped nucleus.And its velocity is 2,54,016 km/h.
I hope u got it !