Digital PSAT Math Practice Question 343: Answer and Explanation

Question: 343

A particular black hole has a density of 1.0 × 10⁶ kg/m³. A physicist is conducting a thought experiment in which she would like to approximate how much she would weigh if she had the density of a black hole rather than her current weight of 150 pounds, assuming her volume remained the same. Given that her overall body density is approximately 990 kg/m³ and that there are approximately 2.2 pounds in a kilogram, approximately how many pounds would she weigh in her thought experiment?

• A. 2,178
• B. 151,500
• C. 990,000,000
• D. 2,178,000,000

Correct Answer: B

Explanation:

(B) Divide 1.0 × 10⁶ kg/m³ by 990 kg/m³ to determine by what multiple her weight will increase. Her weight will be 1,010 times greater. Then multiply 1,010 by 150 pounds to get 151,500 pounds.