Have you read the question back on here and thought- "ah, that looks a mess, I'll reformat it to help readers"
Like this:
A mass breaks suddenly into two parts, masses M and m, with speeds V and v respectively and carrying a total kinetic energy K.
If M / m = R = 4.2, what fractions of K does each of the masses carry? (Think about significant figures.)
a) M carries _____ K. b) m carries _____ K.
Again you must have an idea what principle and equation to use. Tell us what you think. It seems pretty straightforward to me if you spend a few minutes on it