How do I find the probability of these independent events?

Question

The following is taken from the ETS math review for the GRE: Let A, B, C, and D be events for which P(A or B)=0.6, P(A)=0.2, P(C or D)=0.6, and P(C)=0.5 The events A and B are mutually exclusive, and the events C and D are independent. Find P(D). I'd appreciate it if someone could show me how to solve this. The answer is given as 0.2, but I don't know how it's arrived at. Thanks!

Answer 1

Since C and D are independent, we know P(C and D)=P(C)P(D)

We also know P(C or D)=P(C)+P(D)-P(C and D)

Substitute the first equation into the second, so P(C or D)=P(C)+P(D)-P(C)P(D)

Substitute the values you know, .6=.5+P(D)-.5P(D)

Solve for P(D)

.6=.5+P(D)-.5P(D)

.1=.5P(D)

.2=P(D)

Answer 2

According to the text A and B have nothing to do with C and D.

P(C or D) = 0.6

P(C) + P(D) = 0.6

0.5 + P(D) = 0.6

P(D) = 0.1

Perhaps datd left out?