Utopia has a population of 17,000. If 70% of the population voted in the last presidential election, how many people voted in the election?

its 0.7x17000 left out one zero

70% is the same thing as 

$${\frac{{\mathtt{70}}}{{\mathtt{100}}}}$$

or

.7

If we know that .7 of the population voted, we can multiply this by the total population to figure out how many people voted.

$${\mathtt{0.7}}{\mathtt{\,\times\,}}{\mathtt{1\,700}} = {\mathtt{1\,190}}$$

Yes Ninja, you left out a zero.  

But you can have my thumbs up anyway.

for the question that ninja devo asked it is 11,900 people it is simple. you just do 17000 times 0.30 = 5100, then you do 17,000 - 5,100= 11,900