Consider a% of b is x and it is written as,
[tex]\frac{a}{100}\times b=x[/tex]Given that 15% of x =16 , to find the value of x,
[tex]\begin{gathered} \frac{15}{100}\times x=16 \\ \frac{15}{100}=\frac{16}{x} \end{gathered}[/tex]Hence the correct expression for 15% of x =16 is 15/100=16/x
Answer: option 4) 15/100=16/x is correct.