Let R be the set of families having a car and T, the set of families having a scooter. Then n(RT)
= the number of families having at least one of car and scooter.
= 2,000 - 73 = 1,927
n(R) = 894 and n(T) = 287
Let x families who have only car = 894 - x
Number of families who have only scooter = 287 - x
From Venn Diagram,
894 - x + x - 287 - x = 1,927
⇒ 607 - x = 1,927
x = 1,927 - 607
x = 1,320
Hence, the required number of families having both car and scooter = 1,320