Question

B and C have a frictionless pulley, in each case the height is the same.

If Fb and Fc are the forces that have to exert on b and c respectively, then

Fc = Fb
Fc = 1/3Fb
Fc = 2Fb
Fc = 1/2Fb

Answer 1

I just don't know how to aproach to this problem

Answer 2

fc=1/2fb

Answer 3

you must remember that on the string the tension is the same everywhere so, that implies that on the pulley mantaining the weight there is one upward force on the left and one on the right which are the same, so you need half the force you needed on Fb,
so:
\[F_c=F_b/2\]