Answer:
t=9.7 seconds
Step-by-step explanation:
It is given that A skydiver falls under the force of gravity, therefore the initial velocity will be equal to zero that is:

Now, Displacement of the skydiver (when only under gravity),


Also, acceleration due to gravity is given as:

Using the second equation of motion, we have

Substituting the given values, we get

⇒

⇒

⇒

Thus, approximately at the 9.7 seconds the jumper falls before he opens his parachute.