# 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.