Question

plzz do 7th question

Answer 1

OR


Solution:-
A tap can fill a tank = 15 min
Therefore, A tap can fill a tank in a min = 1/15
Another tap can  empty same tank = 20 min
Therefore, Another tap can empty a same tank = 1/20
If both the taps start functioning at the same time, 
Then, time taken by both tap to fill tank in a min = 1/15 – 1/20
 = (4 – 3)/60
 = 1/60
Both tank fill the tank = 60 min

HOPE it HELPS YOU.....