Problem Statement
Two pipes can fill a tank in 12 min and 15 min. If both are opened together, after how many minutes should the first be closed so that the tank is full in exactly 10 minutes?
Explanation
Use 60 units as total work. Rates: 5 and 4 units per minute. Let x be minutes when both are open. Then 9x + 4(10 − x) = 60. Solve to get x = 4 minutes.
Code Solution
SolutionRead Only
9x + 40 − 4x = 60 ⇒ 5x = 20 ⇒ x = 4
