hello
to solve this question, we need to pick each option and simplify it and see if the answer corresponds
a
[tex]\begin{gathered} a.\text{ }\frac{x}{3}+10 \\ x=15 \\ a=\frac{15}{3}+10=5+10=15 \end{gathered}[/tex]
option A is correct, let's test for option b
[tex]\begin{gathered} b \\ \frac{15521}{x} \\ x=15 \\ \frac{15521}{15}=1034.73 \end{gathered}[/tex]
option b does not corresponds to 15 hence it's a wrong option.
let's move to option c
[tex]\begin{gathered} (\frac{3015}{x})-186 \\ x=15 \\ \frac{3015}{15}-186=201-186=15 \end{gathered}[/tex]
option C is correct since the value of the expression is equal to 15
let's check for option D
[tex]\begin{gathered} \frac{20x^2}{30} \\ x=15 \\ \frac{20(15)^2}{30}=\frac{20\times225}{30}=\frac{6750}{30}=225 \end{gathered}[/tex]
option D does not corresponds to 15 and it's a wrong option
let's check for option E
[tex]\begin{gathered} \frac{2x^2}{5}-25 \\ x=15 \\ \frac{2\times15^2}{5}-25=\frac{2\times225}{5}-25=90-25=65 \end{gathered}[/tex]
option E is also incorrect
from the calculations above, only option A and C are correct
