The number of registered vehicles on the road in a country i

The number of registered vehicles on the road in a country is constantly increasing. In 2009, there were approximately 500 million registered vehicles. This represents a 2% increase over 2002. How many registered vehicles were there in the country in 2002? Round to the nearest million.

Solution

The number of registered vehicles on road in 2009 is not very clear. It can be read/interpreted as 300 million. Therefore, we have assumed this figure to be 300 million.

Let the number of registered vehicles on road in 2002 be x. Since the number of vehicles increased by 2 % to 300 million in 2009, we have x + x*2/100 = 300. Or, x + 0.02x = 300 or, 1.02x = 300. Therefore x = 300/ 1.02 = 294.1176471 million = 294 million ( on rounding off to the nearest million).