If it is assumed that 60 percent of those who receive a questionnaire by mail will respond and 300 responses are needed, what is the minimum number of questionnaires that should be mailed?
Choose the correct choice from the following answers:
A) 400
B) 420
C) 480
D) 500
E) 600
Minimum no of mail to be sent for getting 300 responses at 60%   = 300/0.6= 
<gadget id="calculator">300/0.6</gadget>
<output>500</output>
500   Option 500
<result>D</result>
If it is assumed that 60 percent of those who receive a questionnaire by mail will respond and 300 responses are needed, what is the minimum number of questionnaires that should be mailed?