48% of respondents to a survey consisted of those who used both M and N and those who used neither M nor N. 38% of respondents did not use M. 32% used N. What percent of respondents used only N? Choose the most appropriate option:
A) 19.5% B) 11% C) 20% D) 18.5% E) 17.5%
From the question, we can summarize the information as follows:   N Not N   M X   Not M Ans y 38   32 100   Then we can set a system of 3 equations 3 unknowns described below:   X + Y = 48   X + Ans = 32   Y + Ans = 38   Sum up all three equations to get 2X + 2Y + 2Ans = 118   Divide both sides by 2 to get X + Y + Ans = 59   Replace X + Y with 48 to get 48 + Ans = 59   Substract 48 from both sides to get Ans = 59 - 48= 
<gadget id="calculator">59 - 48</gadget>
<output>11</output>
11   The answer must be 11%.
<result>B</result>
48% of respondents to a survey consisted of those who used both M and N and those who used neither M nor N. 38% of respondents did not use M. 32% used N. What percent of respondents used only N?