+0  
 
0
71
1
avatar

There are 5 red, 4 green and 3 blue points on a circle. Find the number of those line segments which have end points of different colors.

 Mar 13, 2020
 #1
avatar+20802 
+1

Each line segment from a red point that goes to either a green point or a blue point has endpoints of different colors.

There are 7 segments from each red point and there are 5 red points, for a total of 35 segments.

 

Each line segment from a green point that goes to either a red point or a blue point has endpoints of different colors.

There are 8 segments from each green point and there are 4 green points, for a total of 32 segments.

 

Each line segment from a blue point that goes to either a green point or a red point has endpoints of different colors.

There are 9 segments from each blue point and there are 5 blue points, for a total of 27 segments.

 

Adding these together, we get 35 + 32+ 27 = 94 segments.

However, we have counted each segment twice, so we need to divide that answer by 2:  47 segments.

 Mar 14, 2020

20 Online Users

avatar
avatar
avatar
avatar
avatar