Total population = 500
15 out of 60 gives a YES response
This implies
Probability of getting a YES response is
[tex]\frac{15}{60}[/tex]Out of the 500 population
The number of YES responses will be
[tex]500\times\frac{15}{60}[/tex]Simplifying this gives
[tex]\begin{gathered} 500\times\frac{15}{60} \\ =500\times\frac{1}{4} \\ =125 \end{gathered}[/tex]Hence out of 500 population 125 responses will be YES
Therefore, the number of NO responses is
[tex]500-125=375[/tex]Therefore, the number of NO responses is 375