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JEE Mains · Maths · STD 11 - 6. permutation and combination
\(5 -\) digit numbers are to be formed using \(2, 3, 5, 7, 9\) without repeating the digits. If \(p\) be the number of such numbers that exceed \(20000\) and \(q\) be the number of those that lie between \(30000\) and \(90000\), then \(p : q\) is
- A \(6:5\)
- B \(3: 2\)
- C \(4:3\)
- D \(5: 3\)
Answer & Solution
Correct Answer
(D) \(5: 3\)
Step-by-step Solution
Detailed explanation
\(p\,:\,\begin{array}{*{20}{c}} 0&0&0&0&0 \\ 5&4&3&2&1 \end{array}\,\,\,\begin{array}{*{20}{c}} {place} \\ {ways} \end{array}\) Total no. of ways \(=5!=120\) Since all numbers are \(>20,000\) \(\therefore \) all numbers \(2,3,5,7,9\) can come at first place.…
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