Consider the first, second, and third horses as A, B, and C, respectively. Let the length of the racecourse be denoted as x.
The distances covered by each horse are as follows:
A B C
x (x-11) (x-90) { from 1st condition}
x (x-80) { from 2nd condition}
Setting up the equation based on the first condition:
\(x - \frac{11}{x} = \frac{x - 90}{x - 80}\)
Simplifying the equation:
⇒ x² - 91x + 880 = x² + 90x
This simplifies further to x = 880