10. Two pipes A and B can fill a tank in 20 and 30 minutes respectively. If both the pipes are used together, then how long will it take to fill the tank?
A. 25 min
B. 12 min
C. 50 min
D. 15 min
10. Two pipes A and B can fill a tank in 20 and 30 minutes respectively. If both the pipes are used together, then how long will it take to fill the tank?
A. 25 min
B. 12 min
C. 50 min
D. 15 min