Step 1: Express the relationship between \( y \) and \( x \).
We are given that \( y = 50% \times 50% \times x = 0.5 \times 0.5 \times x = 0.25x \).
Also, we know that \( y% \times x = 100 \), meaning:
\[
\frac{y}{100} \times x = 100
\]
Substitute \( y = 0.25x \) into the equation:
\[
\frac{0.25x}{100} \times x = 100
\]
Simplify the equation:
\[
0.0025x^2 = 100
\]
Solving for \( x \):
\[
x^2 = \frac{100}{0.0025} = 40,000 \quad \implies \quad x = \sqrt{40,000} = 200
\]
\[
\boxed{1000}
\]