Find the limiting velocity

This is a question i got, which i have NO CLUE how to solve, or what they are asking. Can I please get some help??

It reads:

The velocity of a body of mass m falling from rest under the action of gravity is given by the equation , where k is a constant that depends on the body's aerodynamic properties and the density of the air, g is the gravitational constant, and t is the number of seconds into the fall. Find the limiting velocity, , of a 340lb skydiver (mg = 340) when k=0.006.