Question:easy

How many 3-digit numbers can be formed using three distinct single digit prime numbers?

Show Hint

Count how many single-digit primes exist, then work out how many ways the three digit positions can each independently be filled from that set.
Updated On: Jul 17, 2026
  • 64
  • 24
  • 12
  • 4
Show Solution

The Correct Option is A

Solution and Explanation

Apply the permutation/counting formula directly to the set of usable digits.

The set of usable digits is {2, 3, 5, 7}, a set of size n = 4, since these are exactly the primes less than 10.

Each of the three positions in the 3-digit number is filled independently from this set of 4 digits, giving a total count of 4 x 4 x 4 = 4^3 = 64. Since every digit in {2,3,5,7} is nonzero, all 64 combinations are valid 3-digit numbers with no leading-zero issue.

Final answer: 64.

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