Monthly Archives: January 2021

Trace Without Lifting Pencil

Posted on January 26, 2021 by mvtrinh

Is it possible to trace the following figure without retracing any lines and without lifting your pencil from the paper? If yes, trace the route. If not, explain why it is not possible. Source: NCTM Mathematics Teacher, April 2008 Solution … Continue reading →

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Girl or Boy

Posted on January 21, 2021 by mvtrinh

A woman is chosen at random among all women who have two children. She is asked if she has at least one son and answers yes. What is the probability that her other child is also a boy? Assume that … Continue reading →

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Game of Tossing Coin

Posted on January 2, 2021 by mvtrinh

You are given an initial stake of one dollar. A coin will be tossed indefinitely until it lands on its tails. Every time it lands on heads, your prize will be doubled. When it lands on tails, you walk away … Continue reading →

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Two People Arrival Times

Posted on January 2, 2021 by mvtrinh

Two people arrive at a restaurant independently. Their arrival times are random and uniformly distributed between p.m. and p.m. (no moment in this interval is any more likely for arrival than another). What is the probability that the two people … Continue reading →

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