If A = {1, 2, 3} and B = {1, 2, 3, 4, 5}, how many subsets of B are also subsets of A?
Answer and explanation
Correct answer: 8
A is a subset of B, so every subset of A is automatically a subset of B. Conversely, any subset of B that is also a subset of A must use only the elements 1, 2, and 3; it cannot contain 4 or 5. Thus the required subsets are precisely all subsets of A. Since A has three elements, its power set has 2³ = 8 subsets, including the empty set and A itself. Therefore option C is correct.
Frequently asked questions
What is the correct answer to this question?
8
Why is this the correct answer?
A is a subset of B, so every subset of A is automatically a subset of B. Conversely, any subset of B that is also a subset of A must use only the elements 1, 2, and 3; it cannot contain 4 or 5. Thus the required subsets are precisely all subsets of A. Since A has three elements, its power set has 2³ = 8 subsets, including the empty set and A itself. Therefore option C is correct.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Power Set and Subsets.
