7. The sum of the numerator and denominator of a certain fraction is 2012, and its value is $\frac{1}{3}$. What is this fraction?
7. Let $x$ be the numerator of the desired fraction. Then $2012 - x$ is the denominator of the desired fraction. 1 point

It holds that: $\frac{x}{2012-x}=\frac{1}{3}$

2 points

$2012-x=3x$. 2 points

$2012=4x$. 1 point

$x=503$. 2 points

The desired fraction is $\frac{503}{1509}$. 2 points

TOTAL 10 POINTS