We know the equation of motion v = u+ at, where v is the final velocity, u is the initial velocity, a is the acceleration and t is the time taken.
In this case Final velocity = -3.1 m/s, negative sign indicates it is pointing downward.
acceleration = - 3.7m/
. Negative means acceleration is towards center of planet Mars.
Time taken = 3 seconds

So jumping velocity of Julia = 8 m/s