Answer
$D=53m$
Work Step by Step
We are given all of the information needed to find the smallest distance that two speedboats can be from each other, L, using equation (36-17).
$L=\frac{Dd}{1.22 \lambda}$
Solving for D, we obtain :
$D=\frac{L*1.22 \lambda}{d}$
$D=\frac{6.2*10^{3}m*1.22 1.6*10^{-2}m}{2.3m}$
$D=53m$
