1900 would be the answer. And you should state the right answer if you know it so the person who is trying to solve it is sure about the answer before he or she explains it to you Thanks
The way i work it out is think about what the normal output would be if there wasnt any abnormal gain. Which clearly would have been 8000 minus 400 which gives us 7600. Now this 7600 is the output after 20 percent of normal loss so that means 7600/.80 will give us the output if there was no normal loss at all.. which is 9500 so subtract 7600 from 9500 gives us 1900