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Probability Riddle Using Python: Probability of Random Lines Crossing


An urn contains the numbers 1, 2, 3, ..., 2018. We randomly draw, without replacement, 4 numbers in order from the urn, which we will denote a, b, c, d.  What is the probability that the following system will have a solution strictly inside (i.e., not on the axes) the first quadrant?   

ax + by = ab 

cx + dy = cd

Python Solution:

Riddle source: