There are two towns, A and B. In A, population decreases by 10,000 every year.…
2017
There are two towns, A and B. In A, population decreases by 10,000 every year. In B, population increases by 15,000 every year. What should be the difference between initial populations of B and A if their population becomes equal after 30 years?
Answer: C. 750000 — To determine the difference between the initial populations of town A and town B, we can set up an algebraic equation based on the population changes over 30…
- A.
450000
- B.
600000
- C.
750000
- D.
108000
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Correct answer: C
To determine the difference between the initial populations of town A and town B, we can set up an algebraic equation based on the population changes over 30 years.
Step-by-Step Analysis
Define the variables:
Let P_A be the initial population of town A.
Let P_B be the initial population of town B.
Express the population after 30 years:
Town A decreases by 10,000 every year: P_A - (10,000 × 30)
Town B increases by 15,000 every year: P_B + (15,000 × 30)
Set the populations as equal after 30 years:
P_A - 300,000 = P_B + 450,000
Find the difference between initial populations (P_A - P_B):
Rearrange the equation to solve for (P_A - P_B):
P_A - P_B = 450,000 + 300,000
P_A - P_B = 750,000