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

Step-by-step solution

There are 4 !=24 numbers. Each digit occurring 3 !=6 times, in the unit's, ten's, hundred's and thousand's places. We note that (2+4+6+8)=120 . Thus in the over all sum there will be 120 units, 120 tens, 120 hundreds and 120 thousands. The required sum aligned &=120 (1+10+10²+10³ ) &=120 1111=133320 aligned