I'm pretty sure you do 15/35 (fifteen over thirty-five) times x/105 (x over one hundred and five) and cross multiply. If you get a calculator and multiply, you'll find that 15x105 is 1,575, and 35 times x is 35x. Your equation is then 35x=1,575. If you divide 1,575 by 35 you get 45. Another way to check this is by putting 15/35= in a calculator. It'll tell you 3/7. The same thing will happen with 45/105. Also, 105 divided by 35 is three, so you can multiply 15 by three. Either way, the answer is 45 medium per every 105 a rack.
