Question

HELP ME PLEASE!!

Answer 1

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:

$x = 3y$

$z = y - 10$

$15x + 40y + 5z = 3100$

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 3 times as much as at-store service, thus:

$x = 3y$

By mail service costs $10 less than at-store  service, thus:

$z = y - 10$

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

$15x + 40y + 5z = 3100$

The system is:

$x = 3y$

$z = y - 10$

$15x + 40y + 5z = 3100$

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.

$15x + 40y + 5z = 3100$

$15(4y) + 40y + 5(y - 10) = 3100$

$60y + 40y + 5y = 3150$

$105y = 3150$

$y = \frac{3150}{105}$

$y = 30$

Then

$x = 3y = 3(30) = 90$

The cost of one on-site repair service is of $90.

A similar problem is given at brainly.com/question/24823220