hello
in the question, it's states that 15 baseballs weigh 75oz and how many baseball will weigh 15oz
let's equate this and solve it
[tex]\begin{gathered} 15\text{balls}=75oz \\ \text{xballs}=15oz \end{gathered}[/tex]cross multiply and solve for x
[tex]\begin{gathered} 15\times15=75\times x \\ x=\frac{225}{75} \\ x=3 \end{gathered}[/tex]therefore, 3 balls will weigh 15oz