SOLUTION: A tea set has 4 cups and saucers.Two of which are of same color and the other two are of different color.If the cups are placed randomly on the saucers.What is the probability that

Suppose the cups are A, B, C, and D

Suppose the saucers are W, X, Y, and Z

where the color of the letter is the color of the cup or saucer,

Then there are only four ways to place them successfully

(A, W), (B, X), (C, Y), (D, Z)

(A, W), (B, X), (C, Z), (D, Y)

(A, X), (B, W), (C, Y), (D, Z)

(A, X), (B, W), (C, Z), (D, Y)

To place them any old way, there are 4 ways to place a cup on saucer A,
which leaves 3 ways to place a cup on saucer B, which leave 2 ways to place a
cup on saucer C, which leaves 1 way to place a cup on saucer D.
That's 4x3x2x1 = 4! = 24 ways

So the probability is 4 ways out of 24 ways or  or 

Edwin