Question

The population of a city in 2005 was 15,000. By 2015, the city's population had grown to 45,000 people. Assuming that the population of the city has grown linearly since 2005 and continued to grow at the same rate, what will be the population in 2025?

Answer 1

The population of the city in the year 2025 will be 85,000.

Explanation:

The population of the city in year 2005 = 15,000

The population of the city in the year 2015 = 45,000

⇒ The change in population in 10 years

= Population in year 2015 - Population in the year 2005

= 45,000 - 15, 000

= 30,000

⇒ The change in population in 10 years = 30,000

Now, the population in the year 2015 = 45, 000

Let us assume the number of population in the year 2025 = m

Here, according to the question:

Since, the CHANGE OF RATE is a linear growth since 2005.

⇒ The change in population in each 10 years = 30,000

⇒ The change in population in next 10 years

= Population in year 2025 - Population in the year 2015

or, 30, 000 = m - 45, 000

⇒ m = 30,000 + 45,000 = 85,000

or, m = 85,000

Hence, the population of the city in the year 2025 will be 85,000.