?% of 280 + 18% of 550 = 143.8 (a) 11 (b) 18 (c) 21 (d) 16 (e) None of these
y/100*280+18/100*550=143.8y/100*280+99=143.8y/100*280=143.8-99y/100*280=44.8y=44.8*100/280y=16