Mathematics · Functions

JEE Main 2024 — 8 April, Shift 1 — Question 14

Let [t][\mathrm{t}] be the greatest integer less than or equal to t. Let A be the set of al prime factors of 2310 and f:A→Zf: A \rightarrow \mathbb{Z}

be the function f(x)=[log⁡2(x2+[x35])]f(x)=\left[\log _{2}\left(x^{2}+\left[\frac{x^{3}}{5}\right]\right)\right]. The number of one-to-one functions from A to the range of ff is :

  1. Option A:

    20

  2. Option B:

    120

    Correct
  3. Option C:

    25

  4. Option D:

    24

Answer: B

Step-by-step solution

N=2310=231×10\mathrm{N}=2310=231 \times 10

=3×11×7×2×5=3 \times 11 \times 7 \times 2 \times 5

A={2,3,5,7,11}A=\{2,3,5,7,11\}

f(x)=[log⁡2(x2+[x35])]f(x)=\left[\log _{2}\left(x^{2}+\left[\frac{x^{3}}{5}\right]\right)\right]

f(2)=[log⁡2(5)]=2f(2)=\left[\log _{2}(5)\right]=2

f(3)=[log⁡2(14)]=3\mathrm{f}(3)=\left[\log _{2}(14)\right]=3

f(5)=[log⁡2(25+25)]=5\mathrm{f}(5)=\left[\log _{2}(25+25)\right]=5

f(7)=[log⁡2(117)]=6\mathrm{f}(7)=\left[\log _{2}(117)\right]=6

f(11)=[log⁡2387]=8\mathrm{f}(11)=\left[\log _{2} 387\right]=8

Range of f:B={2,3,5,6,8}\mathrm{f}: \mathrm{B}=\{2,3,5,6,8\}

No. of one-one functions =5!=120=5!=120

Answer key and solution verified before publishing.

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Exam
JEE Main 2024
Subject
Mathematics
Chapter
Functions
Topic
One-One, many-one, onto, into, bijective functions
Let [ t ] be the greatest integer less than or equal to t. Let A be… | JEE Main 2024 PYQ with Solution · DhiX AI