Answer:
Assuming the weight is the same in both cases and in the first system there is only 1 pulley, then in the second case must be 2 pulleys, because the end of the rope is pulled double than before.
In the second case, therefore, the force applied is half than the first case, and that´s the mechanical advantage of a multiple wheel pulley. In the 2 pulleys system, the mass is supported by two sections of the same rope instead of just one and this means you can lift the mass by pulling with a force which is half of the mass weight.