Answer:
x = 3
Step-by-step explanation:
[tex]\begin{array}{rcll }\dfrac{x}{8} & = & \dfrac{7.5}{20} &\\\\x & = & 8\times \dfrac{7.5}{20}&\text{Multiplied each side by 8}\\\\ & = & \dfrac{60}{20} & \text{Simplified}\\\\ & = & \mathbf{3} & \text{Cancelled the 20s}\\\end{array}[/tex]
Check:
[tex]\begin{array}{rcl}\dfrac{3}{8} & = & \dfrac{7.5}{20 }\\\\0.375 & = & 0.375\\\end{array}[/tex]
It checks.