• 📢 2024 results - 20% Students got invitation from top 10 selective schools.
  • 📢 2024 results - 69% Success Rate.
  • ✍️ Prepare with online topic-wise tests.
  • 📢 The 2025 New South Wales (NSW) Selective High School Placement Test will take place from Friday, May 2 to Sunday, May 4
  • 📢 New Free Online Batch Starting from 10th March 2025, 7Pm to 8:30Pm

To estimate the salmon population,

Question: To estimate the salmon population, Professor Cain and her research team marked 360 salmon with tags. Later, the team captured 350 salmon, 21 of which had tags. To the nearest whole number, what is the best estimate for the salmon population?
(1) 6000
(2) 3300
(3) 5999
(4) 6100

Solution:

The ratio of marked salmon to total salmon should be about the same in both the sample population and the overall population. You know how many salmon were in the sample and how many of those were marked. You also know the total number of marked salmon.

Set up a proportion.
marked salmon counted / total salmon counted = total marked salmon / estimated salmon population
Plug in the numbers you know and solve for the salmon population, p.
21/350 = 360/p
21/350(350p) = 360/p(350p) Multiply both sides by 350p
21p = 360*350
21p = 126000
p = 6000
The best estimate for the salmon population is 6000.
Then the option is (1).

Leave a Comment

Your email address will not be published. Required fields are marked *