A card is drawn from a standard deck of 52 cards. What is the probability that it is a black card?

(Express your answer as a fraction in its simplest form.)

(a)  

A bag contains 8 black pens, 12 green pens, and 10 red pens. If a pen is drawn at random, what is the probability that it is a black pen or a red pen?

(Express your answer as a fraction in its simplest form.)

(a)  

Of 150 students, 60 students are studying Math, 50 are studying Science, and 20 are studying both Math and Science. A student is chosen at random. Find the probability that the student is studying Math or Science.

(Express your answer as a fraction in its simplest form.)

(a)