Four people are needed to lift a tv set with a single fixed pulley. how many people will be needed to lift the same tv set with a 2 fixed, 2 moveable pulley system? (ignore friction.)

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.