Algebra-2

Question Analysis
This problem assesses the ability to solve a rational equation in a real-world context, specifically involving rates and proportions.

Key Concept Explanation
The problem involves setting up and solving a rational equation based on the given information about the rates of the two pipes.

Step-by-step Solution
1. Let be the time it takes to fill the tank when both pipes are open.
2. The rate of the first pipe is of the tank per hour, and the rate of the second pipe is of the tank per hour.
3. Combined rate equation: .
4. Find a common denominator: