Question 77
A is a set of all integers between 1 and 100 ( both included ) that are multiples of 6. B is a set of all integers between 1 and 200( both included ) that are multiples of 8. How many elements are in the set C = B-(A$$\cap$$B)?
Solution
The set A consists of integers between 1 and 100 that are multiples of 6.
The set B consists of integers between 1 and 200 that are multiples of 8.
(A$$\cap$$B) is the set of multiples of LCM(6, 8) = 24, between 1 to 100.
(A$$\cap$$B) = {24, 48, 72, 96}
The size of B is 200/8 = 25.
So, the size of C = 25-4 = 21.
