Answer
40 feet away from the center (opposite).
Work Step by Step
Step 1. Based on the given conditions, we have $a=50, b=30$ and the equation of the ellipse can be written as
$\frac{x^2}{50^2}+\frac{y^2}{30^2}=1$
or
$\frac{x^2}{2500}+\frac{y^2}{900}=1, y\geq0$
Step 2. Using the above results, we have $c=\sqrt {a^2-b^2}=\sqrt {1600}=40\ ft$. Thus they should stand, in opposite, 40 feet away from the center.
