A tank is filled in 5 hours by three pipes P, Q and R. The pipe R is twice as…
2022
A tank is filled in 5 hours by three pipes P, Q and R. The pipe R is twice as fast as Q and Q is twice as fast as P. How much time will pipe P alone take to fill the tank?
- A.
22 hrs
- B.
25 hrs
- C.
30 hrs
- D.
35 hrs
Attempted by 9 students.
Show answer & explanation
Correct answer: D
Let the rate of pipe P be x. Since Q is twice as fast as P, Q's rate is 2x. R is twice as fast as Q, so R's rate is 4x.
Combined rate of P, Q, and R = x + 2x + 4x = 7x.
The tank is filled in 5 hours, so total work = rate × time = 7x × 5 = 35x.
Time for pipe P alone to fill the tank = total work / rate of P = 35x / x = 35 hours.
हिन्दी उत्तर: माना नल P की दर x है। Q, P से दुगुनी गति से चलता है, इसलिए Q की दर 2x है। R, Q से दुगुनी गति से चलता है, इसलिए R की दर 4x है।
P, Q और R की संयुक्त दर = x + 2x + 4x = 7x।
टैंक 5 घंटे में भरता है, इसलिए कुल कार्य = दर × समय = 7x × 5 = 35x।
नल P अकेले टैंक भरने में लगा समय = कुल कार्य / P की दर = 35x / x = 35 घंटे।