Change set

Pick exam & year, then Go.

Question map
Not attempted Correct Incorrect ★ Bookmarked
Loading…
Q12 (CISF/2019) Science & Technology › Basic Science (Physics, Chemistry, Biology)

A water tank can be filled by a pipe in 4 minutes and by a smaller pipe in 12 minutes. If both the pipes are opened simultaneously, in how much time will the tank be filled?

Explanation

To find the time taken when both pipes are opened simultaneously, we calculate their combined rate of work:

  • Rate of the first pipe = 1⁄4 tank per minute
  • Rate of the smaller pipe = 1⁄12 tank per minute

Combined rate = 1⁄4 + 1⁄12

To add these fractions, we use a common denominator (12):
Combined rate = 3⁄12 + 1⁄12 = 4⁄12 = 1⁄3 tank per minute.

The total time taken to fill the tank is the reciprocal of the combined rate:
Time = 1 ÷ (1⁄3) = 3 minutes.

Therefore, if both pipes are opened together, the tank will be filled in 3 minutes.

✓ Thank you! We'll review this.

SIMILAR QUESTIONS

CAPF · 2017 · Q79 Relevance score: 7.11

Two pipes A and B can fill a tank in 12 minutes and 16 minutes respectively. If both the pipes are opened together, then after how much time, B should be closed so that the tank is full in 9 minutes ?

CAPF · 2024 · Q1 Relevance score: 3.72

Two taps A and B can fill a tank with water in 20 minutes and 15 minutes, respectively. A third tap C can empty the full tank in 6 minutes. After the taps A and B fill the tank for 5 minutes, the tap C is opened to empty while A and B continue to fill it. In how many minutes after the start shall the tank get empty?

IAS · 2007 · Q112 Relevance score: 0.35

Three identical vessels A, B and C are filled with water, mercury and kerosene respectively up to an equal height. The three vessels are provided with identical taps at the bottom of the vessels. If the three taps are opened simultaneously, then which vessel is emptied first?

CAPF · 2023 · Q91 Relevance score: -0.27

Suppose A, B and C are three taps fixed to the bottom of a tank with draining capacity 1 : 2 : 3. When all three of them are on, it takes 1 hour to drain out the full tank. If A and C are on but B is off, then how much time, in minutes, will it take to empty out a full tank of water? (a) 75 (b) 90 (c) 105 (d) 120

IAS · 1998 · Q134 Relevance score: -0.64

If 15 pumps of equal capacity can fill a tank in 7 days, then how many extra pumps will be required to fill the tank in 5 days?