Respuesta :
Answer:
The correct option is 4. The total costs will be the same at 12 months.
Step-by-step explanation:
The given equations represents the cost of each ISP as a function of t, the duration in months of a service contract.
ISP A:
[tex]C(t)=180+10t[/tex]
ISP B:
[tex]C(t)=25t[/tex]
Equate both the functions to find the time at which the total costs to be the same.
[tex]180+10t=25t[/tex]
Subtract 10t from both the sides.
[tex]180+10t-10t=25t-10t[/tex]
[tex]180=15t[/tex]
Divide both sides by 15.
[tex]\frac{180}{15}=t[/tex]
[tex]12=t[/tex]
The total costs will be the same at 12 months. Therefore the correct option is 4.