Question

somewhere, the cost of making copies at store w is $10 regardless of the number of copies. the cost of making copies at store z is $0.80 per copy plus a $1 charge for the use of the machine. the total cost to be the same at both stores. use pencil and paper. if you have to make a small number of copies which store should you go to? if you have to make a large number of copies which store should you go to?
write the system of equations. choose the correct answer below.
a
store w
store z
c = 0.80n - 10
c = 1
b
store w
store z
c = 10
c = 0.80n + 1
c
store w
store z
c = 10
c = 0.80n + 1
d
store w
store z
c = 10
c = 0.80n - 1

Explanation:

Step1: Define cost equations

Store W: $c = 10$ (flat rate)
Store Z: $c = 0.60n + 1$ (per-copy + fixed fee)

Step2: Set costs equal, solve for $n$

Set $10 = 0.60n + 1$
Subtract 1: $9 = 0.60n$
Solve for $n$: $n = \frac{9}{0.60} = 15$

Step3: Analyze small/large copy counts

For $n < 15$: Test $n=10$
Store W: $c=10$, Store Z: $c=0.60(10)+1=7$ → Store Z is cheaper.
For $n > 15$: Test $n=20$
Store W: $c=10$, Store Z: $c=0.60(20)+1=13$ → Store W is cheaper.

Answer:

1. System of equations:

Store W: $c = 10$
Store Z: $c = 0.60n + 1$

1. The cost is the same at 15 copies.
2. For a small number of copies (fewer than 15), choose Store Z (it has a lower total cost). For a large number of copies (more than 15), choose Store W (its flat rate becomes cheaper than Store Z's per-copy + fixed fee structure).
3. Correct option: C. Store W: $c=10$; Store Z: $c=0.60n+1$