Digital PSAT Math Practice Question 20: Answer and Explanation

Question: 20

A marine biologist has conducted research into the population of blue whales over the past few decades. The estimated global blue whale population is plotted against the given year in the graph below:

A worldwide treaty prohibiting commercial whaling (i.e., the hunting of whales) was passed at some point between 1930 and 2010. Based on the data, what is the year when this treaty most likely went into effect?

• A. 1930
• B. 1950
• C. 1970
• D. 2000

Correct Answer: C

Explanation:

(C) After the passage of a treaty banning whaling, it is most reasonable to expect that the population of blue whales would gradually increase. 1970 is the only choice after which there is an increase in the global blue whale population.