A, B and C went bird watching. Each of them saw one bird that none of the others did. Each pair saw one bird that the third did not. And one bird was seen by all three. Of the birds A saw, two were yellow. Of the birds B saw, three were yellow. Of the birds C saw, four were yellow.

(a) How many yellow birds were seen in all?
(b) How many non-yellow birds were seen in all?

A total of 7 birds are distributed as follows with yellow birds denoted by 'y' and non yellow bird denoted by 'n'. '_'signifies a place holder containing no bird.

A B C
y y y
n _ _
_ y _
_ _ y
n n _
_ y y
y _ y

a) there are 5 yellow birds
b) there are 2 non yellow birds.


Edited on August 30, 2003, 8:26 pm
Edited on August 30, 2003, 8:28 pm

Posted by cat on 2003-08-30 20:19:35