These two frogs can change places in three moves. The yellow frog starts in the leftmost box.
- A frog can either hop onto an adjacent square, or jump over one other frog to the vacant square immediately beyond it.
- The yellow frogs can only move from left to right.
- The green frogs can only move from right to left.
- The frogs shown can be interchanged in 15 moves. Explain how.
- Now suppose that there are an unequal number of green and yellow frogs. These frogs can be interchanged in 11 moves. Explain how.