Okay, so I have this sum:

"A printer numbers the pages of a book starting with 1 and uses 3189 digits in all. How many pages the book have?

Options:

a) 1074

b) 1075

c) 1000

d) None of the above"

My solution:

"The total number of pages have 3189 digits. (given)

⇒ the number of combinations= 9*10³¹⁸⁸.

∴ The total number of numbers= 9*10³¹⁸⁸*3189!

∴d) None of the above"

The Book's Solution:

"1 digit numbers have 9 digits (9 numbers)

2 digit numbers have 180 digits (90 numbers)

3 digit numbers have 2700 digits (900 numbers)

4 digit numbers have 300 digits (75 numbers)

[since total number of digits is 3189, hence

Number of digits for 4 digit numbers

=3189-(9+180+27000)= 300]

Total number of pages

= 9 +90 +900 +75= 1074"

So, according to them, the correct answer is a) 1074, but for me its d) None of the above.

Please help

Note: The solution of the book is almost verbatim, with marginal changes in the format.

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And this is my performance this year:
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alright so basically we have 1 over x²+1

we make shure that x can't be equal to 1 or -1 stay with but why don't we do this

√x²≠√-1

x≠i

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