How to calculate the glide distance?
Basic Math:

How long will the plane be in the air?

$\frac{9842.52 ft\ \text{AGL}}{800\ fpm} = 12\ \text{minutes}$



How far will the plane go in 12 minutes?
$68kts \cdot \frac{12\ minutes}{60\ min/hr} = 13\ \text{NM}$

Assumptions


Assuming no tail wind or head wind, so that KIAS relates to actual ground-speed.
Approximating that 68 KIAS is the ground-speed, when it is in fact the slant-distance speed.   If you need a precise answer, apply the Pythagorean Theorem to refine the answer.