Jane is looking at a tree. At the same time, the tree and Jane are casting shadows - the tree of 10 meters and Jane of 0.5 meters. Jane is 1.5 meters tall. How tall is the tree? Think carefully first, then make a decision:
The shadow of Jane is 1.5 / 0.5 = 3 times smaller than her height. The height of the tree is therefore 3 times bigger than the shadow, so it's 3 * 10 = 30 meters tall. So, the answer is 30.