Mathematics/General Ability MCQs
Topic Notes: Mathematics/General Ability
MCQs and preparation resources for competitive exams, covering important concepts, past papers, and detailed explanations.
Plato
- Biography: Ancient Greek philosopher (427–347 BCE), student of Socrates and teacher of Aristotle, founder of the Academy in Athens.
- Important Ideas:
- Theory of Forms
- Philosopher-King
- Ideal State
1
A tank is filled by two pipes in 19 min and 25 min respectively, and drained by a third pipe in 31 min. How long to fill the tank if all operate together?
Answer:
16.56
Step-by-step solution: 1. Filling rates: 1/19 + 1/25. 2. Draining rate: 1/31. 3. Net rate = 1/19 + 1/25 - 1/31 = 0.0604 tank/min. 4. Time = 1 / net rate = 16.56 minutes.
2
A tank is filled by two pipes in 15 min and 21 min respectively, and drained by a third pipe in 31 min. How long to fill the tank if all operate together?
Answer:
12.19
Step-by-step solution: 1. Filling rates: 1/15 + 1/21. 2. Draining rate: 1/31. 3. Net rate = 1/15 + 1/21 - 1/31 = 0.0820 tank/min. 4. Time = 1 / net rate = 12.19 minutes.
3
A tank is filled by two pipes in 20 min and 20 min respectively, and drained by a third pipe in 32 min. How long to fill the tank if all operate together?
Answer:
14.55
Step-by-step solution: 1. Filling rates: 1/20 + 1/20. 2. Draining rate: 1/32. 3. Net rate = 1/20 + 1/20 - 1/32 = 0.0688 tank/min. 4. Time = 1 / net rate = 14.55 minutes.
4
A tank is filled by two pipes in 17 min and 22 min respectively, and drained by a third pipe in 34 min. How long to fill the tank if all operate together?
Answer:
13.36
Step-by-step solution: 1. Filling rates: 1/17 + 1/22. 2. Draining rate: 1/34. 3. Net rate = 1/17 + 1/22 - 1/34 = 0.0749 tank/min. 4. Time = 1 / net rate = 13.36 minutes.
5
A tank is filled by two pipes in 15 min and 20 min respectively, and drained by a third pipe in 30 min. How long to fill the tank if all operate together?
Answer:
12.0
Step-by-step solution: 1. Filling rates: 1/15 + 1/20. 2. Draining rate: 1/30. 3. Net rate = 1/15 + 1/20 - 1/30 = 0.0833 tank/min. 4. Time = 1 / net rate = 12.0 minutes.
6
A tank is filled by two pipes in 15 min and 21 min respectively, and drained by a third pipe in 30 min. How long to fill the tank if all operate together?
Answer:
12.35
Step-by-step solution: 1. Filling rates: 1/15 + 1/21. 2. Draining rate: 1/30. 3. Net rate = 1/15 + 1/21 - 1/30 = 0.0810 tank/min. 4. Time = 1 / net rate = 12.35 minutes.
7
A tank is filled by two pipes in 19 min and 23 min respectively, and drained by a third pipe in 34 min. How long to fill the tank if all operate together?
Answer:
14.99
Step-by-step solution: 1. Filling rates: 1/19 + 1/23. 2. Draining rate: 1/34. 3. Net rate = 1/19 + 1/23 - 1/34 = 0.0667 tank/min. 4. Time = 1 / net rate = 14.99 minutes.
8
A tank is filled by two pipes in 16 min and 26 min respectively, and drained by a third pipe in 32 min. How long to fill the tank if all operate together?
Answer:
14.34
Step-by-step solution: 1. Filling rates: 1/16 + 1/26. 2. Draining rate: 1/32. 3. Net rate = 1/16 + 1/26 - 1/32 = 0.0697 tank/min. 4. Time = 1 / net rate = 14.34 minutes.
9
A tank is filled by two pipes in 19 min and 21 min respectively, and drained by a third pipe in 32 min. How long to fill the tank if all operate together?
Answer:
14.49
Step-by-step solution: 1. Filling rates: 1/19 + 1/21. 2. Draining rate: 1/32. 3. Net rate = 1/19 + 1/21 - 1/32 = 0.0690 tank/min. 4. Time = 1 / net rate = 14.49 minutes.
10
A tank is filled by two pipes in 18 min and 21 min respectively, and drained by a third pipe in 33 min. How long to fill the tank if all operate together?
Answer:
13.72
Step-by-step solution: 1. Filling rates: 1/18 + 1/21. 2. Draining rate: 1/33. 3. Net rate = 1/18 + 1/21 - 1/33 = 0.0729 tank/min. 4. Time = 1 / net rate = 13.72 minutes.