Contingency Tables · Exercise 17

Use the information in the to answer the next eight exercises. The table shows the political party affiliation for various members of the U.S. Senate during two separate years when they are up for reelection.
$$\begin{array}{ccccc}\text{Up for reelection:}& \text{Democratic Party}& \text{Republican Party}& \text{Other}& \text{Total}\\ \text{Year A}& \text{20}& \text{13}& \text{0}& \\ \text{Year B}& \text{10}& \text{24}& \text{0}& \\ \text{Total}& & & & \end{array}$$

Suppose that a member of the U.S. Senate is randomly selected. What is the probability that the senator is up for reelection in Year A, knowing that this senator is a Republican?

Its source prints no answer for this problem, so there's nothing to check against.

OpenStax, Introductory Statistics 2e · §3.4 Contingency Tables · Exercise 17