A pipe can empty a tank in 12 minutes and another pipe can empty it in 16 minutes. If both the pipes are opened simultaneously, find the time in which a full tank is emptied?

Pipes A and B can fill the tank in 12 and 16 hours respectively. Therefore,
part filled by pipe A in 1 hour = 1/12
part filled by pipe B in 1 hour = 1/16

the quantity filled if all the pipes are opened together = 1/12 + 1/16

amit says

how 66/7comes

Saran Harika says

Pipes A and B can fill the tank in 12 and 16 hours respectively. Therefore,

part filled by pipe A in 1 hour = 1/12

part filled by pipe B in 1 hour = 1/16

the quantity filled if all the pipes are opened together = 1/12 + 1/16

==> [(16+12)/ 192] ( L. C. M of 16 & 12)

==> (28 / 192)

==> (7 / 48)

Required time = 48 / 7 = 6 6/7

Raja Mishra says

plzz repeat sir

Saran Harika says

Pipes A and B can fill the tank in 12 and 16 hours respectively.

Therefore,part filled by pipe A in 1 hour = 1/12

part filled by pipe B in 1 hour = 1/16

the quantity filled if all the pipes are opened together = 1/12 + 1/16

==> [(16+12)/ 192] ( L. C. M of 16 & 12)

==> (28 / 192)

==> (7 / 48)

Required time = 48 / 7 = 6(6/7)

Srilatha says

mam here it is saying about emptying the tank in mins.. I don’t get it !!

Vamsi says

Pipes A and B can empty the tank in 12 and 16 hours respectively.

Therefore,part empty by pipe A in 1 hour = 1/12

part empty by pipe B in 1 hour = 1/16

the quantity empty if all the pipes are opened together = 1/12 + 1/16

==> [(16+12)/ 192] ( L. C. M of 16 & 12)

==> (28 / 192)

==> (7 / 48)

Required time = 48 / 7 = 6(6/7)

sonika j says

s it is in min

Vamsi says

yes. the answer is in minutes

Soumi saha says

Need the answer plz

Vamsi says

the answer is 6(6/7). none of these check it once