<p><a href="http://www.collegeboard.com/prod_downloads/sat/satguide/SAT_full_0405.pdf%5B/url%5D">http://www.collegeboard.com/prod_downloads/sat/satguide/SAT_full_0405.pdf</a> It's the official SAT practice test for 2004-2005</p>

<p>i'm stuck on Section 6 Question 6. Level 4 problem according to answer key.</p>

<ol>

<li>n = 1234567891011.......787980</li>

</ol>

<p>The integer *n* is formed by writing the positive integers

in a row, starting with 1 and ending with 80, as shown

above. Counting from the left, what is the 90th digit

of *n* ?

(A) 1

(B) 2

(C) 3

(D) 4

(E) 5</p>

<p>Right answer is E.</p>