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📊 Math
Q. Pipe A can fill a tank in 10 hours while pipe B can empty it in 15 hours. If both are opened together, how long will it take to fill the tank?
  • (A) 20 hours
  • (B) 25 hours
  • (C) 30 hours
  • (D) No filling
💬 Discuss
✅ Correct Answer: (C) 30 hours

Explanation: Net rate = 1/10 − 1/15 = 1/30.

📊 Math
Q. Two pipes can fill a tank in 12 hours and 18 hours respectively. An outlet pipe can empty the tank in 36 hours. How long will the tank take to fill?
  • (A) 9 hours
  • (B) 10 hours
  • (C) 12 hours
  • (D) 18 hours
💬 Discuss
✅ Correct Answer: (C) 12 hours

Explanation: Net rate = 1/12 + 1/18 − 1/36 = 1/12.

📊 Math
Q. A pipe fills a tank in 14 hours. Due to a leak, it takes 21 hours to fill. In how many hours can the leak empty the full tank?
  • (A) 42 hours
  • (B) 28 hours
  • (C) 21 hours
  • (D) 14 hours
💬 Discuss
✅ Correct Answer: (A) 42 hours

Explanation: Leak rate = 1/14 − 1/21 = 1/42.

📊 Math
Q. Pipe A can fill a tank in 8 hours and pipe B can fill it in 16 hours. Pipe C empties the tank in 12 hours. If all are opened together, the tank will be filled in?
  • (A) 6 hours
  • (B) 8 hours
  • (C) 12 hours
  • (D) No filling
💬 Discuss
✅ Correct Answer: (C) 12 hours

Explanation: Net rate = 1/8 + 1/16 − 1/12 = 1/12.

📊 Math
Q. Two inlet pipes fill a tank in 5 hours and 10 hours respectively. If an outlet pipe empties the tank in 20 hours, how long will the tank take to fill?
  • (A) 4 hours
  • (B) 5 hours
  • (C) 6 hours
  • (D) 8 hours
💬 Discuss
✅ Correct Answer: (A) 4 hours

Explanation: Net rate = 1/5 + 1/10 − 1/20 = 1/4.

📊 Math
Q. Pipe A fills a tank in 6 hours, pipe B in 12 hours. After 3 hours, pipe A is closed. How long will pipe B take to fill the remaining tank?
  • (A) 2 hours
  • (B) 3 hours
  • (C) 4 hours
  • (D) 6 hours
💬 Discuss
✅ Correct Answer: (B) 3 hours

Explanation: Work done in 3 hrs = 3(1/6+1/12)=3/4. Remaining = 1/4 → B takes 3 hrs.

📊 Math
Q. Pipe A fills a tank in 15 hours and pipe B empties it in 20 hours. Pipe C fills it in 30 hours. If all are opened together, how long will it take to fill the tank?
  • (A) 30 hours
  • (B) 60 hours
  • (C) No filling
  • (D) 20 hours
💬 Discuss
✅ Correct Answer: (B) 60 hours

Explanation: Net rate = 1/15 + 1/30 − 1/20 = 1/60.

📊 Math
Q. A tank can be filled by pipe A in 24 hours and pipe B in 32 hours. Both pipes are opened alternately for 1 hour each, starting with A. In how many hours will the tank be filled?
  • (A) 13 hours
  • (B) 14 hours
  • (C) 15 hours
  • (D) 16 hours
💬 Discuss
✅ Correct Answer: (B) 14 hours

Explanation: Work in 2 hours = 1/24+1/32 = 7/96. Remaining work calculated gives total ≈ 14 hours.

📊 Math
Q. Pipe A can fill a tank in 9 hours and pipe B in 18 hours. If pipe A works for 3 hours and then pipe B alone finishes the work, how long will the total work take?
  • (A) 6 hours
  • (B) 7 hours
  • (C) 8 hours
  • (D) 9 hours
💬 Discuss
✅ Correct Answer: (A) 6 hours

Explanation: A does 1/3 work. Remaining 2/3 done by B in 12 hours → total 15 hours.

📊 Math
Q. Two pipes can fill a tank in 16 hours and 24 hours respectively. A third pipe empties it in 48 hours. How long will it take to fill the tank?
  • (A) 12 hours
  • (B) 16 hours
  • (C) 24 hours
  • (D) No filling
💬 Discuss
✅ Correct Answer: (B) 16 hours

Explanation: Net rate = 1/16 + 1/24 − 1/48 = 1/16.