Respuesta :
Answer:
Option (B) is correct .
The constant of proportionality is 7.5 .
Reason
Let us assume that the number of books be x.
Let us assume that the cost of books be y .
Than
[tex]y \propto x[/tex]
y = kx
Where k is constant of proportionality .
As given
Number of Books 4 6 8
Cost ($) 30 45 60
Thus
when x = 4 , y = 30
Put in the equation y = kx .
[tex]30 = 4k[/tex]
[tex]k = \frac{30}{4}[/tex]
k = 7.5
when x = 6 , y = 45
Put in the equation y = kx .
[tex]45 = 6k[/tex]
[tex]k = \frac{45}{6}[/tex]
k = 7.5
when x = 8 , y = 60
Put in the equation y = kx .
[tex]60 = 8k[/tex]
[tex]k = \frac{60}{8}[/tex]
k = 7.5
Therefore the constant of proportionality is 7.5 i.e option (B) is correct .
Answer:
B.
Step-by-step explanation:
I took the K12 test so the answer above is correct
