# baby walk puzzle

• Mar 8th 2007, 07:36 PM
ggw
baby walk puzzle
Imaging your baby was born and learn how to walk, each step by step. As like as you going to school grade by grade. Here is the puzzle to show that how many ways you can approach this.

How many distinct ways are there to get from
point A to point B in the grid below? Here is the rules are that you may only
move in combinations of up and right along the lines of the grid.
• Mar 8th 2007, 08:59 PM
CaptainBlack
Quote:

Originally Posted by ggw
Imaging your baby was born and learn how to walk, each step by step. As like as you going to school grade by grade. Here is the puzzle to show that how many ways you can approach this.

How many distinct ways are there to get from
point A to point B in the grid below? Here is the rules are that you may only
move in combinations of up and right along the lines of the grid.

The number of ways of getting to a node is the sum of the number of ways of getting to the nodes immediately to the left and below the current node.

(if the node is on the boundary it is the same as its one node either to its left or below it).

So just label each node in the diagram with the corresponding sum, with the bottom left node initially set at 1 to get what is shown in the attachment:

So we see the answer is 128 - or it would be if there wasn't an error in my arithmetic, but there is so it ain't.

If you do the arithmetic correctly you will find the answer is 132

RonL
• Mar 9th 2007, 08:55 AM
ggw
I wondered how you get 13 & 19 ?

i got 132 ways
• Mar 9th 2007, 01:06 PM
CaptainBlack
Quote:

Originally Posted by ggw
I wondered how you get 13 & 19 ?

i got 132 ways

Arithmetic error, cant add on the fly, but if you found the answer then my job here is done:cool:

RonL
• Mar 9th 2007, 05:28 PM
distance
i got 128

2^((15-1)/2) = 128

Captainbalck is correct, you got to check yours
• Mar 15th 2007, 09:27 PM
ggw
no it's not. It should be 132.