Hello, tukeywilliams!

It's easier than you think . . .

The height of the marble is given by: .An elevator ascends from the ground with uniform speed.

At time a boy drops a marble through the floor.

The marble falls with uniform acceleration m/sē

. . and hits the ground seconds later.

Find the height of the elevator at time .

. . where: .

The problem begins when the marble is dropped.

Hence: .

. . . . . .

. . . . . .

We have: .

We are told: .when

So we have: .

. . Therefore: .