Respuesta :
Given:
b jointly varies with a and c. This can be written as,
[tex]b=kac[/tex]
where k is a constant.
We need to determine the value of a when b = 72 and c = 2
Value of k:
Also, given that the value b = 112 when a = 12 and c = 7.
Hence, substituting these values in the expression [tex]b=kac[/tex], we get;
[tex]112=k(12)(7)[/tex]
[tex]112=84k[/tex]
[tex]\frac{4}{3}=k[/tex]
Thus, the value of k is [tex]k=\frac{4}{3}[/tex]
Value of a:
The value of a can be determined by substituting b = 72, c = 2 and [tex]k=\frac{4}{3}[/tex] in the expression [tex]b=kac[/tex], we have;
[tex]72=\frac{4}{3}a(2)[/tex]
[tex]72=\frac{8}{3}a[/tex]
[tex]72\times \frac{3}{8}=a[/tex]
[tex]9=a[/tex]
Therefore, the value of a is 9.
