A: The answers differ by a factor of 60—your approach calculated gallons per minute while the question asks for gallons per hour. Always pay close attention to what units the problem is asking for and use dimensional analysis throughout; both methods (water horsepower and fundamental potential energy) are valid, but you must convert to the correct final units.

A: Yes, that approach is perfectly valid and faster—use it on the exam. But I'd encourage you to also practice the formula manipulation approach during studying to build flexibility and deeper understanding. Like a baseball player learning multiple pitches, having multiple solution methods gives you optionality and confidence on test day, and the different approaches actually reinforce each other conceptually.

A: No, that equation is absolutely fine and will give you the correct answer. However, I recommend also understanding the foundations-based approach using the work-energy principle (power = work/time, work = potential energy change) because knowing multiple solution methods makes you a more flexible problem solver.