Mathematics
Write all 4-digit numbers that can be formed with the digits 2 and 5, using both digits equal number of time. Also find their sum.
Answer
We are required to write 4-digit numbers using only the digits 2 and 5, with each digit used the same number of times. So each digit is used twice.
The digits to be arranged are 2, 2, 5 and 5.
The possible 4-digit numbers are:
2255, 2525, 2552, 5225, 5252, 5522.
Sum = 2255 + 2525 + 2552 + 5225 + 5252 + 5522
= 23,331
Hence, the required 4-digit numbers are 2255, 2525, 2552, 5225, 5252 and 5522, and their sum is 23,331.
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