Q. What is the sum of all 4-digit numbers less than 2000 formed by the digits 1, 2, 3 and 4, where none of the digits is repeated?
(a) 7998
(b) 8028
(c) 8878
(d) 9238
Correct Answer: (a) 7998
Question from UPSC Prelims 2023 CSAT
Explanation :
4-Digit Numbers Sum
The 4-digit numbers less than 2000 formed by the digits 1, 2, 3, and 4 where none of the digits is repeated are 1234, 1243, 1324, 1342, 1423, and 1432.
Adding these numbers together gives the sum:
1234 + 1243 + 1324 + 1342 + 1423 + 1432 = 7998
So, the correct answer is (a) 7998.