ii) A plate holds 7 cup cakes, each with a different colour icing,
and 4 brownies, each of a different size. Find the number of different
ways these 11 cakes can be arranged in a row if no brownie is next to
another brownie.

iii) A plate of biscuits holds 4 identical chocolate biscuits, 6
identical shortbread biscuits and 2 identical gingerbread biscuits.
These biscuits are all placed in a row. Find how many different
arrangements are possible if the chocolate biscuits are all kept
together.