Let set A contains families which own a phone and set B contain families which own a car.
If 65 families own neither a phone nor a car, then 35 will own either a phone or a car
∴n(A∪B)=35
Also we know that
n(A∪B)=n(A)+n(B)−n(A∩B)
35=25+15−n(A∩B)
n(A∩B)=5
5 families own both phone and car and it is given to be 2000 .
∴5
1005x=2000
x=40000
Hence, (i),(ii) and (iii) are correct.