A tank holds 1800 litres. Pipe P fills it at 60 litres per minute, pipe Q fills it at 90 litres per minute and pipe R empties it at 30 litres per minute. Match List-I with List-II.
| List-I | List-II | ||
| (A) | Minutes taken by P alone to fill the empty tank | (I) | 12 |
| (B) | Minutes taken by P and Q together to fill the empty tank | (II) | 15 |
| (C) | Minutes taken by P, Q and R together to fill the empty tank | (III) | 30 |
| (D) | Minutes taken by R alone to empty the full tank | (IV) | 60 |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (A)-(III), (B)-(I), (C)-(II), (D)-(IV)
In each case, time = capacity ÷ net rate.
(A) Minutes taken by P alone to fill the empty tank
This matches (III) 30.
\(1800 \div 60 = 30\)
(B) Minutes taken by P and Q together to fill the empty tank
This matches (I) 12. Together they fill \(60 + 90 = 150\) litres per minute.
\(1800 \div 150 = 12\)
(C) Minutes taken by P, Q and R together to fill the empty tank
This matches (II) 15. The net rate is \(60 + 90 - 30 = 120\) litres per minute.
\(1800 \div 120 = 15\)
(D) Minutes taken by R alone to empty the full tank
This matches (IV) 60.
\(1800 \div 30 = 60\)