In the last student election, Tara received 45% of the votes cast. Her only opponent, Kimberly, received 3,949 votes. How many people voted for Tara in the election?
You need to find $\displaystyle y$ the amount of votes Tara recieved given $\displaystyle y = x - 3949$ where $\displaystyle x$ is the amount of votes in total.
So we must find $\displaystyle x$ first
$\displaystyle 55\% \times x = 3949$
$\displaystyle \frac{55}{100} \times x = 3949$
Can you take it from here?