Back-calculating past population: The current population is 1058400 and grows at 5% per annum. What was the population 2 years ago?

Introduction / Context:Given the present population and a known annual growth rate, we reverse compound to find the population two years earlier.

Given Data / Assumptions:

• P_now = 1058400.
• Annual rate r = 5%.
• We need P_past such that P_now = P_past * (1.05)^2.

Concept / Approach:P_past = P_now / (1.05^2) = 1058400 / 1.1025.

Step-by-Step Solution:

Verification / Alternative check:Exact multiplication confirms the reverse calculation without long division.

Why Other Options Are Wrong:

• Other figures do not yield 1058400 when multiplied by 1.1025.

Common Pitfalls:Subtracting 10% once (linear thinking) instead of reversing compound growth.

Final Answer:960000