If a man weighs 40kgs plus half a man how much does he weigh?

Answer 1

Since 'a' means 'any' then this question resupposes that all man weigh equal. 40Kg must be equal to half a man because it is the only other number we are given. Therefore he equals 80kg.

Of course you could equally say 40Kgs plus-we don't know who the half the man is.