Mark bed takes up 2/5 of the floor space in his room. If Mark''s room takes up 1/8 of the floor space in his house, what fraction of the floor space in the entire house does this bed take up?

His bed is 2/5 of his room, which is 1/8th of the house. In order to know how much of the entire houre the bed takes we have to multiply this: (2/5) * (1/8). When we multiply fractions, we can multiply "independently" the numerator and denominator, like this:

(2*1) / (5*8)

That's 2/40, or 1/20. So his bed takes up 1/20 of his house.