Kinematics

A ball is dropped from rest from the top of a
building with height h and strikes the ground with a
speed v. From ground level, a second ball is thrown
straight upward at the same instant that the first
ball is dropped. The initial speed of the second ball
is v0 = v, the same speed with which the first ball
will eventually strike the ground. Ignoring air
resistance, the balls cross paths:

a. at half the height of the building.
b. above the halfway point of the building.
c. below the halfway point of the building.
d. there is not enough information to determine
where they cross.