Answer:
A box contains 5 green pencils and 7 yellow pencils.
Two pencils are chosen at random from the box without replacement.
=> There are two cases:
1st pick green & 2nd pick yellow: P = 5/12 x 7/11 = 0.265
1st pick yellow & 2nd pick green: P = 7/12 x 5/11 = 0.265
Add up both cases, the probability they are different colors:
P = 0.265 + 0.265 = 0. 53
Hope this helps!
:)