1. Home
  2. PSAT Test
  3. Math Multiple-Choice Tests

PSAT Math Multiple-Choice Practice Question 500

Question: 500

Research scientists are testing the effect of a new antibiotic on bacterial growth. They start with a colony of 1,500 bacteria and take counts every 10 minutes for an hour, as shown in the table below.

Bacterial Count Over Time Following Antibiotic Treatment

Minutes (m)

Number of bacteria (b)

10

1,390

20

1,280

30

1,170

40

1,060

50

950

60

840

Which of the following represents the best interpretation of the y-intercept of the line created when these data points are plotted in the xy-plane if minutes, m, are plotted on the x-axis and number of bacteria, b, are plotted on the y-axis?

Correct Answer: A

Explanation:

A

The question asks about the interpretation of the line of best fit for a graph. The horizontal axis represents minutes, m, and the vertical axis represents the number of bacteria, b. The resulting graph would have a negative slope since b decreases as m increases. The question asks about the y-intercept, which would occur when m = 0. Therefore, the y-intercept must represent the number of bacteria at the start of the experiment. Only (A) reflects this. The correct answer is (A).

More Tests

All content of site and practice tests © 2022 Jack.
Quick View
PSAT Practice Tests
More Information