PSAT Math Multiple-Choice Question 135: Answer and Explanation

Question: 135

Types of Pets	Percent of pets
Dogs	40%
Cats	25%
Fish	15%
Birds	20%
Total	100%

The table above shows the distribution of pets at a pet shop. How many pets are at the pet shop if there are 36 more dogs than cats?

• A. 240
• B. 120
• C. 60
• D. 48

Correct Answer: A

Explanation:

A

The question asks for the number of pets in the pet shop. Since the question asks for a specific value and the answer choices contain numbers in decreasing order, plug in the answers. Begin by labelling the answers as "total pets" and start with (B), 120. If there are 120 total pets and 40% of those pets are dogs, then 120 × 0.40 = 48 of the pets are dogs. If 25% of those pets are cats, then 120 × 0.25 = 30 of the pets are cats. Therefore, there are 48 - 30 = 18 more dogs than cats. The question states that there are 36 more dogs than cats, so eliminate (B). Since the numbers of cats and dogs were too close together, the total number of pets must be too small; eliminate (C) and (D) as well. If this isn't obvious, do the calculations on (A), 240. With 240 total pets, there would be 96 dogs and 60 cats, or 36 more dogs than cats. The correct answer is (A).