Answer:
[tex]c=15d[/tex]
Step-by-step explanation:
we know that
A relationship between two variables, x, and y, represent a proportional variation if it can be expressed in the form [tex]k=\frac{y}{x}[/tex] or [tex]y=kx[/tex]
Let
c ----> the total cost of the boat rental
d ---> is the number of days, the family rents the boat
we know that
Kaya's family spends $105 to rent a boat for 7 days
so
For d=7 days, c=$105
Find the value of the constant of proportionality k
[tex]k=\frac{c}{d}[/tex]
substitute the given values
[tex]k=\frac{105}{7}=\$15\ per\ day[/tex]
therefore
The linear direct equation is equal to
[tex]c=15d[/tex]
