+0  
 
-1
185
5
avatar

How many paths are there from C to D, if we can only move right or down and must stay on the grid? (Its not 220.)

 Mar 30, 2020
 #1
avatar+663 
+2

Look at this video.

 

By using the water flow method.

 

We get a final answer of 126 + 84 = lolololol

 Mar 30, 2020
 #5
avatar+1421 
0

This approach makes more sense to me. ( I watched the video )  smiley

(Instead of  CD  I put  AB )  cheeky  

 

Dragan  Mar 30, 2020
edited by Dragan  Mar 30, 2020
edited by Dragan  Mar 30, 2020
 #2
avatar+112417 
+3

We have the  set ...... ( R, R , R ,R, D, D, D , D , D , D)

 

We can choose  any  4 of 10  positions in the set to place  the R  or  6  of 10 postions in the set  to place  the D

 

We  can  either  use    C(10, 4)   or C(10,6)   =  210 paths

 

 

 

 

cool cool cool

 Mar 30, 2020
 #3
avatar+663 
+1

Another method, and more efficient!

AnExtremelyLongName  Mar 30, 2020
 #4
avatar+112417 
0

I don't know.....yours  is pretty good, too, AELN   !!!!

 

I gave  you a point  !!!!

 

cool cool cool

CPhill  Mar 30, 2020

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