Question 471074

Let total number of person = x

Number of person that preferred to use self-service = 3x/16

number of persons that not preferred to use self-service = 5x/8

and number of  remaining persons that had no clear preference = 75

these three groups form total number of persons...

3x/16 + 5x/8 + 75 = x

=> 13x/16 + 75 = x

=> 75 = x - 13x/16

=> 75 = 3x/16 

so, x = 400

 Number of person that preferred to use self-service = 3/16 * 400 = 75