In a certain town 25% families own a cellphone, 15% families own a television and 65% families own neither a cellphone nor a television. If 1500 families own both a cellphone and a television. Then the total number of families in the town is

Given that In a town 25% families own a cellphone, 

15% families own a television and

 65% families own neither a cellphone nor a television. it means 35% families own either cell phone or television

Let $x$ be the number of people in the town

hence, use the formula $n\left(A\cup B\right)=n\left(A\right)+n\left(B\right)-n\left(A\cap B\right)$

$\frac{35x}{100}=\frac{25x}{100}+\frac{15x}{100}-1500$

Simplifying the above relation

$\begin{array}{rcl}35x& =& 25x+15x-150000\\ 5x& =& 150000\\ x& =& 30,000\end{array}$

Therefore, the number of population in the town is $\boxed{\mathbf{30}\mathbf{,}\mathbf{000}}$