7 hrs

7 hrs 30 min

5 hrs

5 hrs 30 min

B. 7 hrs 30 min

Net part filled In 1 hour =(1/10)+(1/12)-(1/20)=(8/60)=(2/15).

The tank will be full in __15/2 __hrs = 7 hrs 30 min.

10 min

20 min

40 min

50 min

39 min

40 min

50 min

45min

18 hrs

13 hrs

20 hrs

23 hrs

20 hrs

23 hrs

30 hrs

21 hrs

100 hrs

122 hrs

177 hrs

112 hrs

7 hrs

7 hrs 30 min

5 hrs

5 hrs 30 min