When Jane was just eight years old she developed a bit of a crush on Jim. Jim was eighteen and decided to make a promise to Jane. He carved a heart into a nearby cherry tree and placed his initials inside the heart. The heart was out of Jane’s reach by 16 centimetres. Jim promised to marry Jane when she was tall enough to carve her initials next to his. Jane’s reach increased by 8 centimetres a year, but the tree was growing by 7 centimetres each year.
How old was Jane when she could ask Jim to keep his promise?
If you have not tried to solve it, have a go now. For everyone else, the answer is after the break.
Trees grow from their top, not their bottom. Therefore the heart will remain at the same height above the ground, and so Jane will be able to add her initials when she is ten. As a result, Jim felt something of a fool, and apologised to all concerned.
I have produced an ebook containing 101 of the previous Friday Puzzles! It is called PUZZLED and is available for the Kindle (UK here and USA here) and on the iBookstore (UK here in the USA here). You can try 101 of the puzzles for free here.