Answer:
<h2>After 100 seconds Alyssa catch up with Jenny.</h2>
Explanation:
<h3>Jenny's data:</h3>



<h3>Alyssa's data:</h3>

, because she has a difference of 15 seconds.

Both move at a constant speed, that means there's no acceleration, their speed is always the same.
Now, the equation of each movement is
and
, then we solve this two.
We replace the first equation into the second one

That means after 100 seconds Alyssa catch up with Jenny.