Question

The population of a country was increased in the past 4 years. The annual presentage increases are 20%,25%,30%,10% respectively.What the overall percentage increase in these 4years?

Answer 1

The answer is 114.5%.

Let the original population be denoted by x.

Now, let's go through the percentage increase per year.

Year 1

• x (1 + 20%)
• x (1.2)
• 1.2x

Year 2

• 1.2x (1 + 25%)
• 1.2x (1.25)
• 1.5x

Year 3

• 1.5x (1 + 30%)
• 1.5x (1.3)
• 1.95x

Year 4

• 1.95x (1 + 10%)
• 1.95x (1.1)
• 2.145x

Overall increase : 214.5% - 100% = 114.5%

Hence, the overall percentage increase in these 4 years is 114.5%.