The population of a town increased by 15% in 2018 and 10% in 2019. Due to a pandemic, it decreased by 10% in 2020. What was the percentage increase in the population of the town in 3 years?

13.85%

Let present population = 100x

According to question ,

Increased Population

= \(\frac{100+10}{100}\) × \(\frac{100+15}{100}\) × \(\frac{100-10}{100}\) × 100x

= \(\frac{110}{100}\) × \(\frac{115}{100}\) × \(\frac{90}{100}\) × 100x

= 113.85x

Percentage increase in population = \(\frac{113.85x}{100x}\) × 100

= 13.85%