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प्रश्न
How many three-digit numbers can be formed from the digits 0, 1, 3, 5, 6 if repetitions of digits are not allowed?
उत्तर
Three-digit number is to be formed from the digits 0, 1, 3, 5, 6
When repetition of digits is not allowed 100’s place digit should be a non zero number.
Hence, it can be any one from digits 1, 3, 5, 6
∴ 100’s place digit can be selected in 4 ways
10’s and unit’s place digit can be zero
But digits can’t be repeated
∴ 10’s place digit can be selected in 4 ways and unit’s place digit can be selected in 3 ways
∴ By using fundamental principle of multiplication, total number of two-digit numbers
= 4 × 4 × 3
= 48
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