JEE Main 2026 Mathematics question
The number of functions f : {1, 2, 3, 4} → {a, b, c}, which are not onto, is:
Answer: (B)
Solution
Total functions = 3⁴ = 81. Onto functions (by inclusion–exclusion) = 81 − 3(16) + 3(1) = 36. Not onto = 81 − 36 = 45.