Question 3
Two taps can fill a tank. The following plans each fill it:
• Plan 1: run tap A for 7 hours, close it, then run tap B for 14 hours.
• Plan 2: run tap A for 10 hours, close it, then run tap B for 2 hours.
For Plan 3, run tap A for 5 hours, close it, then run tap B. How long must tap B run?
Model clarification: each plan starts with the same empty tank; both taps have constant flow rates and no water is lost.
• Plan 1: run tap A for 7 hours, close it, then run tap B for 14 hours.
• Plan 2: run tap A for 10 hours, close it, then run tap B for 2 hours.
For Plan 3, run tap A for 5 hours, close it, then run tap B. How long must tap B run?
Model clarification: each plan starts with the same empty tank; both taps have constant flow rates and no water is lost.