(a)[4]
Geoff wants to plant $25$ flowers in a flower-bed. He may choose from $15$ different geraniums, $10$ different roses and $8$ different lilies. He requires at least $11$ geraniums and the same number of roses as lilies. Determine the number of different selections of flowers he can make.
(b)[3]
Determine the number of different ways the $9$ letters in GREENGAGE can be arranged when exactly two of the Gs are adjacent.