How long can a flea stay in the air?

Question

Part A: If a flea can jump straight up to a height of 0.420m , what is its initial speed as it leaves the ground?

Answer: $v=2.87$ m/s

Part B: How long is it in the air?

So I was using the formula $v_f =v_0 +at$, where $a=-9.81$ $m/s^2$, $v_f=0$ m/s, and $v_0=2.87$ m/s (from Part A).

Hence, my final answer is t=0.291. Am I correct or not, because the online software I am using to turn in my homework states otherwise?

Answer 1

assuming it doesn't do more work to keep flying then you have to consider the downward time as well as it is still above ground so answer is $2\cdot0.291=0.585$

Answer 2

It has to drop to zero velocity, then the velocity will continue to decrease to $-2.87$ m/s by the time it hits the ground. You are off a factor $2$