Question

A rock was dropped from a platform on a tower 65 feet above a lake. The rock landed on the bottom of the lake which was 21 feet under the surface of the lake. Where was the rock when it had fallen halfway?

22 feet above the lake
43 feet above the lake
44 feet above the lake
10.5 feet below the surface of the lake

Answer 1

What is the total distance the rock fell? This is where we'll start. It falls 65 feet to the lake, then down another 21 feet. So the rock falls a total of 86 feet. What is half of this?

Answer 2

43