Question 8
As shown in the diagram, a $5\times7$ grid is painted in checkerboard fashion. The length of the side of each square is 1 cm. An ant, starting from $A$ at the top left corner, crawls along the grid lines to $B$ at the bottom right corner. If during its movement, a black square is always on the left side of the ant, what is the minimum distance, in cm, the ant must crawl?
