At a certain committee meeting only associate professors and assistant professors are present. Each associate professor has brought 2 pencils and 1 chart to the meeting, while each assistant professor has brought 1 pencil and 2 charts. If a total of 11 pencils and 16 charts have been brought to the meeting, how many people are present? Choose the correct answer:  A) 6  B) 7  C) 8  D) 9  E) 10
Say there are 'A' associate professors. So we have 2A pencils and A charts.   Say there are 'B' assistant professors. So we have B pencils and 2B charts.   Total pencils are 10 so 2A + B = 11   Total charts are 11 so A + 2B = 16   Add both: 3A + 3B = 27 so A + B = 9   Total number of people = 9   9
<result>D</result>
At a certain committee meeting only associate professors and assistant professors are present. Each associate professor has brought 2 pencils and 1 chart to the meeting, while each assistant professor has brought 1 pencil and 2 charts. If a total of 11 pencils and 16 charts have been brought to the meeting, how many people are present?