🛠️ JEE➗ Maths

Let \(A=\{1,2,3,4\}\) and \(B=\{1,4,9,16\}\). Then the number of many-one functions \(f: A \rightarrow B\) such that \(1…

Q1 FREE PREVIEW

Let \(A=\{1,2,3,4\}\) and \(B=\{1,4,9,16\}\). Then the number of many-one functions \(f: A \rightarrow B\) such that \(1 \in f(A)\) is equal to :

[JEE Main 2025, 22 Jan (Shift 2)]

a

127

b

151

c

163

d

139

✓ Correct answer: b)

151

Explanation

Total number of functions = \({4}^{4}=256\)

One-one functions = \(4!\)

Many-one functions = 256-24 = 232

Many-one functions in which \(1\notin \mathrm{f}(\mathrm{A})\)

\(=3.3.3.3=81\)

Required number of functions =

\(232-81=151\)

Practice more JEE Maths PYQs

See every question on Relations and Functions, or browse the full JEE question bank.

See all questions on Relations and Functions →