7. Five marks exercise problems II

\(A\) can do a piece of work in \(12\) hours, \(B\) and \(C\) can do it \(3\) hours whereas \(A\) and \(C\) can do it in \(6\) hours. How long will \(B\) alone take to do the same work?

 

Time taken by \(B\) alone to complete the work \(=\)  hours