Question

During the last 5 years the population of a town that had 12,00,000 people, increased by 15%. What is the present population of the town?

Answer 1

Hint: We solve this problem by first taking the population of town as 12,00,000. Then we find the increase in the population during the 5 years by multiplying 15% with the population before 5 years, that is 12,00,000. Then we add the obtained value to the population of town before 5 years to find the present population of town.

Complete step-by-step answer:
We are given that the population in a town is 12,00,000 people.
Then we are also given that the population of the town has increased by 15% during the last 5 years.
It means the increase in population is equal to 15% of the total population.
So, we get
Increase in Population $=$ 15% of 12,00,000
Increase in population = $\dfrac{15}{100}\times 12,00,000=1,80,000$
So, we get that the population of the town has increased by 1,80,000 in the last 5 years.
So, total population after 5 years is equal to, sum of population before 5 years and increase in population.
Total Population = Population before 5 years + Increase in population during 5 years
So, by adding them we get,
Total Population = 12,00,000 + 1,80,000
Total Population = 13,80,000
So, the total population of the town after 5 years is 13,80,000.
Hence the answer is 13,80,000.

Note: The common mistake one does while solving this question is one might think that the given percent of increase in population, that is 15%, is for every year and then calculate the increase in population in the first year, then using that finding the increase in population in second year and so on. But here in the question we are given that during 5 years the population has increased by 15%. So, the percentage of increase is for all 5 years included.