Team A beat Team B 10 to 5. What's the chance A led after every single score?

A basketball game ends 10 to 5, every score worth one point, every order of the 15 scores equally likely. The story asks the probability A was strictly ahead after every score. You type your answer and check it. Then you step through the answer and the breakdown.

Why quant interviews test this

The formula is good; the swapping argument is what interviewers really want. The written solution is at /brain-teasers/ballot-problem/solution.

The The Basketball Ballot guide covers how scoring works, the strategy that wins, a worked example and the mistakes most players make.

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