A alone can do work in = 4 hours
A and C together can do any work in = 2 hours
Then, if we subtract 4 by 2 , then we get the result 2.
So, C alone can do a work in 2 hours.
But, B together with C can do any work in = 3 hours
Then, B alone =(3+2) hours
= 5 hours
Hence, B individually can do any work in 5 hours.