The combination of blue and red colour gives
Magenta
Cyan
Yellow
White
On combining primary colours, we get secondary colours. The combination of blue and red colour gives magenta as the secondary colour.
The elements of sets A , B and C are all colours as follows:
A = { Red , Orange , Yellow , Brown } ,
B = { Blue , Yellow , Green , Brown } ,
C = { Black , Brown , White , Grey }
Then, A U B U C is