In order to turn a ratio into a percentage, you have to turn the given fraction into an equivalent fraction with denominator 100. So, you have
[tex] \dfrac{3500}{5000}=\dfrac{x}{100} [/tex]
Solving for x, you get
[tex] x=\dfrac{3500\cdot 100}{5000} = \dfrac{3500}{50} = \dfrac{350}{5} = 70 [/tex]
So, they achieved the 70% of their goal.
