Answer: 2.5
[tex]\frac{p}{a}=\frac{1}{2} => a=2p\\\\\frac{a}{b}=\frac{2}{3}=> b=\frac{3}{2}a=3p\\\\\frac{b}{c}=\frac{5}{1}=>c=\frac{1}{5} b=\frac{3p}{5}\\\\\frac{c}{r}=\frac{3}{2}=>\frac{3p}{5r}=\frac{3}{2}=>\frac{p}{r}=\frac{3}{2}:\frac{3}{5}=2.5[/tex]
Step-by-step explanation:
