Question

A family is going to choose two pets at random from among a group of four animals: a cat, a dog, a bird, and a lizard. Find the probability that the pets that the family chooses will include the lizard.

• A. $1/2$ or $0.5$
• B. $1/3$
• C. $1/4$
• D. $3/4$
• E. $2/5$

Answer 1

The correct option is A $1/2$ or $0.5$

Often, a good way to start probability problems on the SAT is to list all the possibilities, and then count the number that match the given criteria. Using c for cat, d for dog, and so forth, all the possible combinations of two pets are:
cd, cb, cl, db, dl, bl
Since three of the six possible combinations include the lizard, the probability that the two pets chosen by the family include the lizard is $3/6=1/2=0.5$.