## Question

The term digit of 1! + 2! + 3! + … + 49! Is

### Solution

1

We have 1! + 2! + 3! + 4! = 33. Also 5! = 120, 6! = 720, 7! = 5040, 8! = 40320 and 9! = 326880. Thus, the tens digit of

1! + 2! + … + 9! is 1.

Also, note that *n*! is divisible by 100 for all n ≥ 10, so that tens digit of 10! + 11! + … + 49! is zero. Therefore, tens digit of 1! + 2! + … + 49! is 1.

#### SIMILAR QUESTIONS

In the certain test there are *n* questions. In this test 2* ^{k}* students gave wrong answers to at least (

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*n*. If the total number of wrong answer is 4095, then value of

*n*is

If *n* > 1 and *n* divides (n – 1)! + 1, then

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