two integers are chosen at random between $0$ and $10$ what is the probability that they differ by no more than $5$?

There are $\overbrace{6+7+\dots+10+11}^{\frac{17}2\cdot6}+\overbrace{10+\dots+7+6}^{\frac{16}2\cdot5}=91$ ordered pairs that differ by at most $5$ out of $11^2$ ordered pairs. That gives a probability of $$ \frac{91}{121} $$


Clarification: I read "differ by no more than $5$" to mean $\left|x-y\right|\le5$. Then for $0\le x\le5$, there are $x+6$ choices for $y$ and for $6\le x\le10$, there are $16-x$ choices for $y$.


Why The Discrete Probability Might be Greater than the Continuous

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In the image above, the red squares hang down and to the right of the associated points. Thus, the red area, $91$, divided by $121$ represents the discrete probability. The area inside the black hexagon, $75$, divided by $100$ represents the continuous probability.

The red area is definitely greater than the area of the hexagon, but it is being divided by a larger number, so it is hard to tell which will be greater.

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Probability