Information relating to two processes (F and G) was as follows：

　　Process　　Normal loss　　　　　　Input　　　　　Output

　　as % of input　　　(litres)　　(litres)

　　F　　　　　　　　8　　　　　　　　65，000　　 58，900

　　G　　　　　　　　5　　　　　　　　37，500　　 35，700

　　For each process， was there an abnormal loss or an abnormal gain?

　　Process F　　　　Process G

　　A　 Abnormal gain　　 Abnormal gain

　　B　 Abnormal gain　　 Abnormal loss

　　C　 Abnormal loss　　 Abnormal gain

　　D　 Abnormal loss　　 Abnormal loss

　　Solution：

　　Each process must beconsidered separately.

　　Process F： Normal loss is 8%， thus expected output is 92% of input. Input was 65，000 litres. Thus expected output was 59，800 litres. Actual output was 58，900 litres. As actual output was less than expected， there was an abnormal loss. That means that choices A and B are incorrect. However， a common mistake by candidates is to assume that the performance in both processes is the same. Making this mistake leads to the selection of choice D.

　　Process G： Normal loss is 5%， thus expected output is 95% of input. Input was 37，500 litres. Thus expected output was 35，625 litres. Actual output was 35，700 litres. As actual output was more than expected， there was an abnormal gain.

　　Thus the correct choice is C.

　　Another common mistake in questions such as this is to mix up the values for expected output and actual output. Well laid-out workings and a logical approach can help to overcome this problem.

　　Work out your answer：

　　As the incorrect answers are based on common mistakes， it follows that attempting to guess the correct answer is not likely to be productive. Rather it is essential that you use your understanding of the topic to work out your answer. This will prevent you from being distracted by incorrect options.