# Statistics and Probability

## Duel of Two 50% Marksmen: Odds in favor of the man who shoots first

**Problem**

Smith and Jones, both 50% marksmen, decide to fight a duel in which they exchange alternate shots until one is hit. What are the odds in favor of the man who shoots first?

A. 1/3 | C. 2/3 |

B. 1/2 | D. 1/4 |

## Two Gamblers Play Until One is Bankrupt: Chance That the Better Player Wins

**Problem**

Player *M* has Php1, and Player *N* has Php2. Each play gives one the players Php1 from the other. Player *M* is enough better than player *N* that he wins 2/3 of the plays. They play until one is bankrupt. What is the chance that Player *M* wins?

A. 3/4 | C. 4/7 |

B. 5/7 | D. 2/3 |

## Random Steps of a Drunk Man: Probability of Escaping the Cliff

**Problem**

From where he stands, one step toward the cliff would send the drunken man over the edge. He takes random steps, either toward or away from the cliff. At any step his probability of taking a step away is 2/3, of a step toward the cliff 1/3. What is his chance of escaping the cliff?

A. 2/27 | C. 4/27 |

B. 107/243 | D. 1/2 |

## Samuel Pepys Wrote Isaac Newton Asking Which Event is More Likely to Occur

**Problem**

Samuel Pepys wrote Isaac Newton to ask which of three events is more likely: that a person get (*a*) at least 1 six when 6 dice are rolled (*b*) at least two sixes when 12 dice are rolled, or (*c*) at least 3 sixes when 18 dice are rolled. What is the answer?

*a*) is more likely than (

*b*) and (

*c*)

B. (

*b*) is more likely than (

*a*) and (

*c*)

C. (

*c*) is more likely than (

*a*) and (

*b*)

D. (

*a*), (

*b*), and (

*c*) are equally likely

## Spinning Spherical Target: Probability for Three Marksmen to Hit on the Same Hemisphere

**Problem**

Three marksman simultaneously shoot and hit a rapidly spinning spherical target. What is the probability that the three points of impact lie on the same hemisphere?

A. 0 | C. 1 |

B. 1/2 | D. 2/3 |