Recall that the y% of x is given by the following expression:
[tex]x\cdot\frac{y}{100}\text{.}[/tex]Now, let S be the number of people that were in the survey, then, we know that 39% of S is 351, then we can set the following equation:
[tex]351=S\cdot\frac{39}{100}\text{.}[/tex]Multiplying the above equation by 100/39 we get:
[tex]\begin{gathered} 351\times\frac{100}{39}=S\cdot\frac{39}{100}\times\frac{100}{39}, \\ S=900. \end{gathered}[/tex]Answer: 900.
