13. $25/month
14. 36 and 37
Step-by-step explanation:
Let a = monthly rate ($/month)
t = time (months)
k = installation cost
The equation for the cost of the internet service C is
C = at + k
Since C = $685. t = 24 months (2 years) and k = $85, we can solve for a:
at = C - k
or
a = (C - k)/t
= ($685 - $85)/(24 months)
= $25/month
14. Let n = the number
n + 1 = the number after n
Since the sum of two consecutive numbers is 73, we can write the equation as
n + (n + 1) = 73
which simplifies to
2n + 1 = 73
2n = 72
Solving for n, we find that
n = 36
so the other number is 36 + 1 = 37.
