Pipe X, Y and Z can fill a cistern 8 hrs, 12 hrs and 24 hrs respectively. All three began to fill the cistern together but X and Y left 4 hrs and 3 hrs respectively before filling the cistern. What is the total time taken by all of them to fill the cistern?
1
10 hrs
2
7 hrs
3
3 hrs
4
14 hrs
5
None of these