Question

The input work done on a machine is 9.63 × 103 joules, and the output work is 3.0 × 103 joules. What is the percentage efficiency of the machine?

Answer 1

output/input times 100 percent. about under 30% by rounding (down, which is the wrong way) ?
http://perendis.webs.com

Answer 2

my more efficient b$ machine claims \(0.3\color{red}{1..}\) as the answer

as a **sensible** way to measure the energy-in vs the energy-out.....

\( \eta = \dfrac {3.0}{9.63} \approx 0.3\color{red}{1..}\)