## The Pancho Villa Trip

We have three numbers, one in each milestone:

**xy** **yx** ** x0y**

We can see that **x** must be less than **y**, because the distance in the second landmark must be greater than the distance in the first.

We can also conclude that **x = 1**, because the distance between each landmark is a 2-digit number, and the sum of two 2-digit numbers will never result in a value greater than 198.

Then we can write the three numbers as follows:**10 + y** **10.y + 1** **100 + y**

We want to know the speed that Pancho Villa walks.

Let's call this speed z. Then we can assemble the following equations:

**z = (10y + 1) - (10 + y)** and ** z = (100 + y) - (10y + 1)**

Overriding the value of **z** In the second equation we have:

**(10y + 1) - (10 + y)** = **(100 + y) - (10y + 1)9y-9 ** =

**99-9y**

18y = 108

y = 6

18y = 108

y = 6

Now just put this value in the first equation to find the **z**:

**z = (10.6 + 1) - (10 + 6)z = 60 + 1-10-6z = 45**

So Pancho Villa walked at a speed of **45km / h**.

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