Final answer:
The probability that a randomly selected senator is a Republican or up for reelection in November 2014 is 100%.
Step-by-step explanation:
To find the probability that a randomly selected senator is a Republican or is up for reelection in November 2014, we need to determine two things:
Let's assume that there are a total of 100 senators. If 60 senators are Republicans and 40 senators are up for reelection in November 2014, we can calculate the probability as follows:
Probability = (Number of Republicans + Number of senators up for reelection in November 2014) / Total number of senators = (60 + 40) / 100 = 100 / 100 = 1
Therefore, the probability that a randomly selected senator is a Republican or is up for reelection in November 2014 is 1 or 100%.