Question

A tap can fill a water tank in 8 hours and the other can empty it in 12 hours. how much time it takes to fill, if both work simultaneously. . . ​

Answer 1

Answer:

10 hour because tap one fill 8 hour and two fill 12 arithmetic mean of both 20 equal to 10

Answer 2

Answer:

tap can fill the tank in 8 hours

tap can , in 1 hour, fill 1/8 part of tank

other tap can, in one hour, empty 1/12 part of tank

both taps will, in 1 hour, fill (1/8 - 1/12) part of tank

= (3 - 2)/24

= 1/24

thus, on opening both taps, the tank will fill in 24 hours