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JEE Mains · Maths · STD 11 - 6. permutation and combination

The number of natural numbers less than \(7,000\) which can be formed by using the digits \(0, 1, 3, 7, 9\) (repetition of digits allowed) is equal to

  1. A \(250\)
  2. B \(374\)
  3. C \(372\)
  4. D \(375\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(374\)

Step-by-step Solution

Detailed explanation

\(\boxed{{a_1}}\boxed{{a_2}}\boxed{{a_3}}\) Number of numbers \( = {5^3} - 1\) \(\boxed{{a_4}}\boxed{{a_1}}\boxed{{a_2}}\boxed{{a_3}}\) \(2\) ways for \({a_4}\) Numbers of numbers \( = 2 \times {5^3}\) Required number \(0020 = {5^3} + 2 \times {5^3} - 1\) \(= 374\)
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