MathDB

2017 PUMaC Team 14

Source:

September 20, 2019

combinatorics

Problem Statement

Eric rolls a ten-sided die (with sides labeled

1

through

10

) repeatedly until it lands on

3, 5

, or

7

. Conditional on all of Eric’s rolls being odd, the expected number of rolls can be expressed as

\frac{m}{n}

, where

m

and

n

are relatively prime positive integers. Compute

m + n