e A pet shop has four glass tanks in which snakes for sale are held. The shop can stock at most four snakes at any one time because: if more than one snake were held in the same tank, the snakes would attempt to eat each other and having snakes loose in the shop would not be popular with the neighbours. The number of snakes sold by the shop each day is a random variable with the following distribution: Number of Snakes Potentially Sold in Day (if stock is sufficient) None One Two Probability 0.4 0.4 0.2