A gardener has seven identical-looking tulip
bulbs, of which each will produce a different
color tulip. Four of the colors are unknown,
however one will become white, one will
become yellow, and one will become pink. He
plants them abitrarily in a row. When the
flowers start to bloom, what is the probability
that the yellow one is first in the row, the white
one is second, and the pink one is at the end of
the row?
