Question

A women while writing the number from 400 to 599 , mistakenly wrotes 8 every times instead of 4 . So the total number of times she has wrotes 8 is _____?​

Answer 1

Explanation:

2 Answers. By adding the number of times the digit 5 occurs in each position, you have counted each number in which 5 appears exactly two times twice and each number in which 5 appears exactly three times thrice, once for each position in which it occurs, which is why your method produces the right answer.

Answer 2

Answer:

Let's Count those 8 which she would written correctly .

If She wrote Correctly then total Number of 8 be 19 i.e.

408,418,428,438,448,458,468,478,480,481,482,483,484,485,486,487,488,489,498

And the Number of time She written 8 instead of 4 are as usual i.e.

408,418,428,438,448,458,468,478,480,481,482,483,484,485,486,487,488,489,498

So she had written 8 , 38 times