A and B start a two-length swimming race at the same moment but from opposite ends of the pool. They swim in lanes at uniform speeds, but A is faster than B. They first pass at a point 18.5 m from the deep end and having completed one length each 1 is allowed to rest on the edge for exactly 45 sec. After setting off on the return length, the swimmers pass for the second time just 10.5 from the shallow end. The pool will be [[1]]m.
 

In order to calculate the distance travelled by both swimmers when they pass each other for the first time and the distance travelled from the opposite end when they pass each other for the second time, we must first assume that the length of the pool is some x. Now that their respective speeds are constant, the rate at which the distances are travelled should also be constant, resulting in a quadratic equation in x. The outcome is then obtained by additional simplification.

Assume the pool is x feet long. Given that B and A initially leave the deep end at the same time that B travels 18.5 feet and A travels $x-18.5$ feet,

A travels a distance of $x-18.5+10.5$ in the same amount of time as B travels a distance of $18.5+x-10.5$
 from the shallow end.

Here, because the swimming speeds of the different swimmers are constant, their rate of distance travelled is likewise constant, which is further expressed as

$\Rightarrow \frac{18.5}{x-18.5}=\frac{x-8}{x+8}$
As we continue to cross multiple, we arrive at
$\Rightarrow 18.5(x+8)=(x-8)(x-18.5)$
The simplified version of this is now as follows:
$\Rightarrow 18.5x+148=x^2-8x-18.5x+148$
Now, after revoking the common words, we receive,
$\Rightarrow x^2=18.5x+8x+18.5x$
Now that things have been further simplified,
$\Rightarrow x^2=45x$
Now that the common phrase on both sides has been further eliminated, we obtain,

$\therefore x=45$

Hence, the correct answer is 45.