39 min
40 min
50 min
45min
A. 39 min
Part filled in 7 min. = 7*((1/36)+(1/45))=(7/20).
Remaining part=(1-(7/20))=(13/20).
Net part filled in 1min. when A,B and C are opened=(1/36)+(1/45)-(1/30)=(1/60).
Now,(1/60) part is filled in one minute.
(13/20) part is filled in (60*(13/20))=39 minutes.
7 hrs
7 hrs 30 min
5 hrs
5 hrs 30 min
20 hrs
23 hrs
30 hrs
21 hrs
39 min
40 min
50 min
45min
100 hrs
122 hrs
177 hrs
112 hrs
18 hrs
13 hrs
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10 min
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