How many subsets of A = {1, 2, 3, 4, 5, 6} contain neither 3 nor 4? Call the number N.
Sets, relations & functions worksheet with answers
How many subsets of A = {1, 2, 3, 4, 5, 6} contain neither 5 nor 6? Call the number N.
A survey of 65 people finds that 30 own a laptop (L), 39 a tablet (T) and 28 a smartwatch (W). 16 own L and T, 5 own L and W, 15 own T and W, and 2 own all three. How many are in L only?
A survey of 52 people finds that 20 own a laptop (L), 34 a tablet (T) and 22 a smartwatch (W). 13 own L and T, 10 own L and W, 14 own T and W, and 6 own all three. How many are in exactly one of the three sets? Call the number n.
The arrow diagram shows a function f: A → B with A = {1, 2, 3, 4} and B = {a, b, c, d}. Click the description that fits f.
- 1injective, not surjective
- 2surjective, not injective
- 3bijective
- 4neither
How many reflexive relations are there on a set with 2 elements? Call the number N.
Answer key
- 1. N = 16
- 2. N = 16
- 3. |L − (T ∪ W)| = 11
- 4. n = 20
- 5. bijective
- 6. N = 4
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