329.Robot on the Table
★★★random walksIMC Trading
A robot stands on a table 3 cm from the left edge and 17 cm from the right edge. Each step it moves 10 cm left or 10 cm right with equal probability. What is the expected number of steps before it falls off the table?
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The step size is large relative to the table, so only a couple of positions are ever reachable. Enumerate them.
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