Question

In 2010, the total population increased by 50% over that in 2004. In 2004, foreigners from India were y% of the total population and this percentage increased by 10% in 2010. In 2010, foreigners from India as a percentage of total foreigners decreased by 20 % over that in 2004. What is y?

• A. 20%
• B. 9%
• C. 12%
• D. 7%

Answer 1

The correct option is D

7%

Let x be the total population in 2004.

So total population in 2010 = 1.5x

​Foreigners from India in 2004 = $\frac{xy}{100}$ and in 2010 = $\frac{y+10}{100}\times 1.5x$

​Foreigners from India as a percentage of total foreigners in 2004 = $\frac{\left(\frac{yx}{100}\right)}{\left(\frac{2x}{100}\right)}\times 100=50y$

And that in 2010 = $\frac{\left(\frac{(y+10)1.5x}{100}\right)}{\left(\frac{5\times 1.5x}{100}\right)}\times 100=20y+200$

The percentage is reduced by 20% over the given period.

50y - (20y + 200) = 20

y=7.33%