A tank can be filled by two taps X and Y in 5 hrs and 10 hrs respectively while another tap Z empties the tank in 20 hrs. In how many hours can the tank be filled if all 3 taps are kept open?
A. 5
B. 4
C. 7
D. 8
Answer:B
A tank can be filled by two taps X and Y in 5 hrs and 10 hrs respectively while another tap Z empties the tank in 20 hrs. In how many hours can the tank be filled if all 3 taps are kept open?
A. 5 B. 4 C. 7 D. 8