+425 A frog is in the bottom of a dry well 25 metres deep. When the frog jumps up using the wall, it goes up by 3 metres, but goes back down by 2 metres. How many jumps must it take to jump completely out of the well?
+23246 The trick is to remember that after the last jump it will be out of the well and won't be slipping back 2 metres.
So, after the first 22 jumps, it will be up 22 metres from the bottom of the bell and only 3 metres from the top. On the 23rd jump it will be at the top of the wall and so can leave the well.
+23246 The trick is to remember that after the last jump it will be out of the well and won't be slipping back 2 metres.
So, after the first 22 jumps, it will be up 22 metres from the bottom of the bell and only 3 metres from the top. On the 23rd jump it will be at the top of the wall and so can leave the well.
