Work output of a large machine in a factory is 89,000 joules, and it's input is 102,000 joules. Work output of a similar machine is 92,000 joules, and it's work input is 104,000 joules. Which machine has a greater efficiency

(89000/102000) * 100

=87.25%

(92000/104000) * 100

=88.46%

efficiency is (output/input) * 100

if u get confused which way input and output should go, remember the smaller value is always output and it's above in the fraction, then only it's possible to get a efficiency lower than 100.