Chewing Gum boy is the naughtiest and most intelligent student in his class. When asked questions, he always gives the wrong answer to the first question and the right answer to the second question. His teacher caught him eating chewing gum in Math class and asked him the following questions:Teacher: “How many single digit whole numbers are there?”Chewing Gum boy: “Sir, 0, 1, 2 and 4.”Teacher: “How many four digit numbers can you form by using these digits if you cannot use each digit more than once and what will be the sum of all those numbers?”What did Chewing Gum boy reply?

1) 19, 38664
2) 14, 4230845
3) 18, 45108
4) 64, 36864

• The total number of integers that can be formed is 3 × 3 × 2 × 1 = 18 If we write down all these four digits numbers
  the digits 1, 2 and 4 will appear six times each in the thousands place. In the units, tens and hundreds places, 0 will
  appear six times each and the digits 1, 2 and 4 will appear four times each. The sum will be 6(1 + 2 + 4) × 1000 +
  4(1 + 2 + 4) × 111 = 45,108.
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