[tex]\text{Lets make a ratio from the scenario given in the question:}\\\\3:5\\\\\text{We know that they stocked 30 pairs of books}\\\\\text{3 times 10 makes 30, so multiply 10 on the other side of the ratio:}\\\\3:5\\\cdot10\\\\30:50\\\\\text{This means that they will have 50 athletic shoes in stock}\\\\\boxed{\text{50 athletic shoes}}[/tex]
