Question

The sum of all 4 digit numbers that can be formed by using the digits 2, 4, 6, 8 (repetition of digits not allowed) is.

• A. 133320
• B. 533280
• C. 53328
• D. None of these

Answer 1

Answer: (A)

133320

Answer 2

Sum of the digits in the unit place is $6(2 + 4 + 6 + 8) = 120$ units. Similarly, sum of digits in ten place is 120 tens and in hundredth place is 120 hundreds etc. Sum of all the 24 numbers is

$120(1 + 10 + 10^{2} + 10^{3}) = 120 \times 1111 = 133320$