If x/y = 5/z, then 25z^2 =  Choose the correct choice from the following answers.
A) x²y²
B) 25y²/ x²
C) 625x²y²
D) y²/ x²
E) 625y²/ x²
This question is most easily solved by isolating y in the equation and substituting into the expression 25z²:   x/y = 5/z   x = 5y/z   5y = xz   z = 5y/x.   If we substitute 5y/x into the expression for z, we get:   25(5y/x)² = 25(25y²/ x²) = 625y²/ x².   The correct answer is choice (625y²/ x²)
<result>E</result>
If x/y = 5/z, then 25z^2 =