AP EAMCET · Maths · Sets and Relations
If a set \(A\) has \(m\) elements and set \(B\) has \(n\) elements and the number of injections from \(A\) to \(B\) is 2520 . Then, \(m\) is equal to
- A 2
- B 7
- C 6
- D 5
Answer & Solution
Correct Answer
(D) 5
Step-by-step Solution
Detailed explanation
Given, \(|A|=m\) and \(|B|=n\) Total number of injective function from \(A\) to \(B\) is \(\frac{n !}{(n-m) !}\) Given, \(\frac{n !}{(n-m) !}=2520\) Total number of injections from \(A\) to \(B={ }^n P_m=2520\)…
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