since i can't find the answer key, but i want to check whether my calculation is correct, plz help me to do this question.
http://www2.hkedcity.net/sch_files/a/kst/kst-06185/public_html/1.jpg
http://www2.hkedcity.net/sch_files/a/kst/kst-06185/public_html/2.jpg