Introduction to Probability

Question

You are one of six people running for class president. The names of the candidates will be listed in random order on the ballot. Find each probability. Round your answers to the nearest thousandth.

a) Probability your name will be last.

P(last)=

b) Probability the names will be in alphabetical order.

P(alphabetical)=

Answer 1

a) 1/6, since each candidate has a chance to be the last name,

b) 1/6*1/5*1/4*1/4*1/2, because there is 1/6 chance the first name is the "smallest" name, after that among the 5 remaining names, there is 1/5 chance the second name is the "smallest", then 1/4 among four remaining names, and so on.