Answer:
C
Step-by-step explanation:
The graph in this case represents exponential decline.
Using a system of equation, we have that:
a)
- x, which is the cost of on-site service.
- y, which is the cost of at-store service.
- z, which is the cost of by-mail service.
b)
The system is:



c)
The cost of one on-site repair service is of $90.
Item a:
The variables are:
- x, which is the cost of on-site service.
- y, which is the cost of at-store service.
- z, which is the cost of by-mail service.
Item b:
On-site service costs <u>3 times as much as at-store service</u>, thus:

By mail service costs <u>$10 less than at-store</u> service, thus:

Last week, the shop completed <u>15 services on-site, 40 services at-store, and 5 services by mail for total sales of $3100</u>, thus:

The system is:



Item c:
- The cost of one on-site repair service is x.
- First, replacing the first two equations into the third, we find y, and then with it we find x.






Then

The cost of one on-site repair service is of $90.
A similar problem is given at brainly.com/question/24823220
$9.47
I just multiplied the total by the refund percentage to get that number. It’s just like finding a tip.
Let Edy's money be x.
Lucy: 35% more --- (135/100) x
x + (135/100) x = 206.80
(47/20)x = 206.80
47x = 206.8 x 20
47x =4136
x = 88
Edy saved $88.
Lucy saved (135/100)(88) = $118.80