A publisher of mathematics books is sending a questionnaire to everyone on a certain mailing list. From experience, the publisher knows that 60%...

Question

...(continue of the question) of the people receiving the questionnaire will either ignore it or throw it away. Of the remaining group, two thirds will fill out the questionnaire, but then only two thirds of those will remember to mail it back. How many names are on the mailing list if the publisher receives 2560 responses?

Solve and type an equation    

Answer 1

40% of the people receiving the questionnaire wil not throw it out

 

(2/3)(.40)  will fill it out

 

(2/3)(2/3)(.40) will then mail it

 

x = the number of people on the mailing list

 

(4/9)(.4)(x) = 2560

 

(4/9)(x) = 6400

 

4x = 57,600

 

x = 14,400

 

there are 14,400 people's names on the mailing list

 

assuming all of the mail is delivered correctly to the people and delivered back to the sender correctly