Theres a new delivery boy at your company, supposed to drive around delivering a specific number of items to difierent locations. He needs to deliver at least X of an item, while the truck can at most take Y of the item.
If there are more, the truck is will to break down due to the weight. If there are less, that means he hasn't fulfilled the assignment. At the loading station, there's a row of boxes he can bring along.
Each box contains a specified number of items. This driver isn't the sharpest snail on the rock, however. Since he's also too shy to ask for help, he's decided to just choose one entirely random starting point in the row of boxes. Then he chooses a random end point among the boxes from the starting point to the end, inclusive.
All the boxes between those points (inclusive) are loaded onto the truck. You and the other employees have started betting on whether or not the truck breaks
down, he brings to few items along or if he should happen to be lucky enough to fulfil the assignment without any problems. This gets you wondering. What is the actual probability for each of these scenarios to occur? Assume for the sake of this problem that the driver will always be able to fit all the boxes into the truck (after all, he had to have SOME skill, seeing as he was hired).