Chapter 10 Counting Methods and Probability - 10.5 Find Probabilities of Independent and Dependent Events - 10.5 Exercises - Skill Practice - Page 722: 28

See below.

a) In this case the events are independent: the first one has probability $\frac{12}{52}$, and the second one has probability $\frac{4}{51}$. Thus the probability is: $\frac{12}{52}\frac{4}{52}=\frac{3}{169}$ b) In this case the events are not independent: the first one has probability $\frac{12}{52}$, and the second one has probability $\frac{4}{51}$. Thus the probability is: $\frac{12}{52}\frac{4}{51}=\frac{4}{221}$