If A={1,2,3,4}, B={2,4,5}, and C={2,5}, then (A−B)×(B−C)=?
2023
If A={1,2,3,4}, B={2,4,5}, and C={2,5}, then (A−B)×(B−C)=?
- A.
{1,3}
- B.
{1,4}
- C.
{1,3,4}
- D.
{1,3,4,5}
Attempted by 272 students.
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Correct answer: C
Solution:
Compute A − B: remove elements of B = {2,4,5} from A = {1,2,3,4}.
A − B = {1,3}.
Compute B − C: remove elements of C = {2,5} from B = {2,4,5}.
B − C = {4}.
Combine the results (here × is being used as the union of the two resulting sets):
(A − B) ∪ (B − C) = {1,3} ∪ {4} = {1,3,4}.
Answer: {1,3,4}.
Note: If the symbol × had been intended as the Cartesian product, the result would be the set of ordered pairs {(1,4),(3,4)}. The option {1,3,4} matches the union interpretation.