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JAMB Mathematics 1999 Question 41

Question 41

Permutation and Combination

How many two-digit numbers can be formed from the digits 0, 1, 2, 3 if a digit can be repeated and no number may begin with 0?

  1. A.4
  2. B.12
  3. C.16
  4. D.20
Show the answer and explanation

Answer: B (12)

Explanation

The first digit can be 1, 2 or 3 (3 ways) and the second any of the 4 digits, so 3 × 4 = 12.