"Two pipes AS and B can fill a tank in 15 minutes and 20 minutes respectively
Channel: Doubtnut
Date: 2020-04-05

"Two pipes AS and B
 can fill a tank in 15 minutes and 20 minutes respectively. Both the pipes are
 opened together but after 4 minutes, pipe A is turned off. What is the total
 time required to fill the tank?
`10min20\ s e c`
b. `11min45\ s e c`

c. `12min30\ s e c`
d. `\ 14min40\ s e c`"