Question

Question: I just recently took my masters exam and missed passing it by only 3 questions.I had a couple of questions that are still stuck in my head.2 motorsMotor #1 115v 1/2 hp 80% eff.Motor #2 115v 1/2 hp 90% eff.What percent more eff. is motor #2 than Motor #1?A. 11%B. 24%C. 28%D. 60%I chose answer A. it seemed to make the most since, but using the formula I didnt get 11%. Can anyone help me set up this question in a more useful formula?Thanks, Steve

Answer 1

Here is a more useful formula to solve this problem:

Percent efficiency gain = (Efficiency of Motor #2 - Efficiency of Motor #1) / Efficiency of Motor #1  100%

Plugging in the given values:

Percent efficiency gain = (90% - 80%) / 80%  100%

Percent efficiency gain = 10% / 80% * 100%

Percent efficiency gain ≈ 12.5%

Therefore, Motor #2 is approximately 12.5% more efficient than Motor #1. None of the answer choices provided exactly match this value, but answer choice A. 11% is the closest. Flag for review

Answer 2

Here is a more useful formula to solve this problem:

Topic: Motor effiency