Question

In a certain town, $25$% families own a cell phone, $15$% families own a scooter and $65$% families own neither a cell phone nor a scooter. If $1500$ families own both a cell phone and a scooter, then the total number of families in the town is

• A. $10000$
• B. $20000$
• C. $30000$
• D. None of these

Answer 1

The correct option is C $30000$

Let the total population of town be $x$.
$\therefore \frac{25x}{100}+\frac{15x}{100}-1500+\frac{65x}{100}=x$
$\Rightarrow \frac{105x}{100}-x=1500$
$\Rightarrow \frac{5x}{100}=1500\Rightarrow x=30000$