Processing math: 100%

Two pipes, P and Q can fill a cistern in 12 and 15 minutes respectively. Both are opened together, but at the end of 3 minutes, P is turned off. In how many more minutes will q fill the cistern?

  • 17
  • 2
    712
    712
  • 38
  • 4
    814
    814
Answer:- 1
Explanation:-

Solution:
P can fill cistern in 12 minutes
P fills cistern in 1 minute =
112
112
Q can fill cistern in 15 minutes
Q fills cistern in 1 minute =
115
115 part
P and Q together can fill cistern in 1 minute,
=112+115960
=112+115960    part
So, they can together fill cistern in 3 minute,
=3×960920
=3×960920    part
Rest Cistern =
1920
1920  =
1120
1120  part
1120
1120 part cistern must be filled by Q in
1120115=814
1120115=814   minutes

Alternatively,
Pipe P can fill cistern in one minute =
10012
10012 = 8.33%
Pipe Q can fill cistern in one minute =
10015
10015 = 6.66%
(P + Q) together can fill the cistern in one minute = 15%;
In 3 minutes cistern is filled = 45%
P become off, then rest of cistern will be filled by Pipe Q in =
556.66
556.66 =
814
814 minutes.

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Q can fill cistern in 15 minutes
Q fills cistern in 1 minute =
115
115 part
P and Q together can fill cistern in 1 minute,
=112+115960
=112+115960    part
So, they can together fill cistern in 3 minute,
=3×960920
=3×960920    part
Rest Cistern =
1920
1920  =
1120
1120  part
1120
1120 part cistern must be filled by Q in
1120115=814
1120115=814   minutes

Alternatively,
Pipe P can fill cistern in one minute =
10012
10012 = 8.33%
Pipe Q can fill cistern in one minute =
10015
10015 = 6.66%
(P + Q) together can fill the cistern in one minute = 15%;
In 3 minutes cistern is filled = 45%
P become off, then rest of cistern will be filled by Pipe Q in =
556.66
556.66 =
814
814 minutes. ", "dateCreated": "7/24/2019 10:09:12 AM", "author": { "@type": "Person", "name": "Nitin Sir" } }, "suggestedAnswer": { "@type": "Answer", "text": "
Solution:
P can fill cistern in 12 minutes
P fills cistern in 1 minute =
112
112
Q can fill cistern in 15 minutes
Q fills cistern in 1 minute =
115
115 part
P and Q together can fill cistern in 1 minute,
=112+115960
=112+115960    part
So, they can together fill cistern in 3 minute,
=3×960920
=3×960920    part
Rest Cistern =
1920
1920  =
1120
1120  part
1120
1120 part cistern must be filled by Q in
1120115=814
1120115=814   minutes

Alternatively,
Pipe P can fill cistern in one minute =
10012
10012 = 8.33%
Pipe Q can fill cistern in one minute =
10015
10015 = 6.66%
(P + Q) together can fill the cistern in one minute = 15%;
In 3 minutes cistern is filled = 45%
P become off, then rest of cistern will be filled by Pipe Q in =
556.66
556.66 =
814
814 minutes. ", "dateCreated": "7/24/2019 10:09:12 AM" } }
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