question_answer

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)         40000

E)  50000

Correct Answer: C

Solution :

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