Suppose we have four boxes A,B,C and D containing coloured marbles as given
below:
Box
Marble colour
Red
White
Black
A
1
6
3
B
6
2
2
C
8
1
1
D
0
6
4
   One of the boxes has been selected at random and a single marble is drawn from
it If the marble is red, what is the probability that it was drawn from box A , box B ,
box C