The rock which is faster than the other have more kinetic energy.
<u>Explanation:</u>
Two rocks are of same mass are rolled down the hill at different speeds. Before the rocks are rolled, at rest they both will have same potential energy and zero kinetic energy. When the rocks are rolled, their potential energy reduces as they move forward and their kinetic energy increases from zero.
Since they are travelling at different speeds, one will be faster than the other, and so one rock reached faster than the other. The rock which reaches the ground first will have more kinetic energy than the other.