- A24
- B30
- C36
- D48
View written solutionFree
Correct answer: B
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Digits available
We can form 4-digit numbers using the digits without repetition.
We want numbers:
- between and
- divisible by
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Condition for being between 2000 and 5000
Since the number is 4-digit and must lie between and , its thousands digit can only be:
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Condition for divisibility by 3
A number is divisible by if the sum of its digits is divisible by .
The available digits are .
Their residues modulo are:
We must choose 4 distinct digits from these 5 digits.
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Find which 4-digit selections give sum divisible by 3
Total sum of all 5 digits is: and
If we omit one digit , then the sum of the chosen 4 digits is: For divisibility by :
Among , the digits congruent to are:
So the valid 4-digit sets are obtained by omitting either or :
- Set 1:
- Set 2:
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Count arrangements from each valid set with first digit or
Case 1: Digits
Total permutations of these 4 digits:
But numbers cannot start with . Number starting with :
Hence valid 4-digit numbers from this set:
All these have first digit among , so all lie between and .
Case 2: Digits
Total permutations:
Numbers starting with :
So 4-digit numbers formed:
But to be between and , first digit must be or only.
Count directly:
- First digit : remaining 3 digits can be arranged in ways
- First digit : remaining 3 digits can be arranged in ways
Total for this case:
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Total count
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Compare with options
The required number is:
So the correct option is B.
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