Let the savings be X and Y and rates of simple interest be 5x and 4x respectively. Then
\( \Large X \times 5x \times \frac{1}{2} \times \frac{1}{100} = Y \times 4x \times \frac{1}{2} \times \frac{1}{100} \)
= \( \Large \frac{X}{Y} = \frac{4}{5} \)
=\( \Large X : Y = 4 : 5 \)