Answer:
b=3
Step-by-step explanation:
If b is inversely proportional to c then
[tex]b=\frac{k}{c}[/tex]
b is 5 when c is 12, means...
[tex]5=\frac{k}{12}[/tex]
From where we obtain the value of k, the constant needed, which is equals to 5*12=60
Now... to find b when c=20, is just a matter of using our known variables.
[tex]b=\frac{60}{20}=3[/tex]
