Asian's weight increased by 25% from year 2005 to 2009. If his weight was k kilograms in 2009, what was it in 2004?

Asian's weight increased by 25% from year 2005 to 2009. If his weight was k kilograms in 2009, what was it in 2004?

Explanation

Asian's weight increased by 25% from 2005 to 2009.

This means his weight in 2009 is 125% of his weight in 2005:

Weight in 2009 = 1.25 × Weight in 2005

Given his weight in 2009 is k kilograms:

k = 1.25 × Weight in 2005

To find his weight in 2005:

Weight in 2005 = k / 1.25 = 0.8k

Since the question asks for his weight in 2004, and we don't have any information about changes in 2004:

Weight in 2004 is assumed to be the same as Weight in 2005.