There is a road shown in the figure below.
I can move forward on the road expressed by the solid line at a speed of 2 times more than the road expressed by the dotted line.
How many ways of method to go from A to B in fastest time are there?
Answer
15 ways
Solution
The method to be able to reach in the shortest time is the way that I move just twice on the road of the dotted line.
Answer
15 ways
Solution
The method to be able to reach in the shortest time is the way that I move just twice on the road of the dotted line.
Thus, the road of the X cannot be passed in the lower figure.
Therefore, there are 15 ways in total when it is counted as shown in the lower figure.
