# Math

posted by P

a photocopy store advertises the following prices: 5 cents per copy for the first 20 copies, 4 cents per copy for the 21st through 100th copy, and 3 cents per copy after the 100th copy. Let x be the # of copies, and let y = the total cost of the photocopying. find the equation in the form y = mx+b that tells you the cost of making x copes when x is more than 100.

1. Damon

20 for 1.00
then 4*.80 = 3.20 for 21 through 100
so
4.20 for 100

y = 4.20 + .03 (x-100)

y = .03 x - 1.20

2. P

Thank you!

3. uthpala

cost for 0 copy to 20 copy =\$ 1

cost for 21 copy to 100 copy = 0.04*80 =\$ 3.2

cost for 101 copy to 200 copy) = 0.03*100 =\$ 3

then cost for 0 copy to 100 copy must be 4.2 dollars and the total cost for 200 copies must be 7.2 dollars.

thus =>

(y- 7.2)/(x-200) = (7.2-4.2)/(200-100)

(y- 7.2)/(x-200) = 0.03

(y- 7.2) = 0.03x - 6

y = 0.03x + 7.2 - 6

y = 0.03 + 1.2

4. Uthpala

y = 0.03x + 1.2

## Similar Questions

1. ### Solving a system of linear Equations using Substit

Suppose a school club publishes a newslettter. Expenses are 90 cents for mailing and printing each copy, plus 600 total for research and writing. The price of the neewsletter is a 1.50 per copy. How many copies of the newletter must …
2. ### math

The president of the country PTA organization makes copies of membership lists for all of the elementary schools. Sometimes she may need only few copies but at other times she needs thousands of copies. TIP copy Service charges 3 ½ …
3. ### math

The president of the country PTA organization makes copies of membership lists for all of the elementary schools. Sometimes she may need only few copies but at other times she needs thousands of copies. TIP copy Service charges 3 ½ …
4. ### math

I cant figure this thing out fully, I feel so clueless. Does anyone have any pointers or tips for me?
5. ### Math Problem

Company A rents copiers for a monthly charge of \$240 plus 8 cents per copy. Company B rents copiers for a monthly charge of \$480 pluse 4 cents per copy. What is the number of copies above which Company A's charges are the higher of …
6. ### algebra

Company A rents copiers for a monthly charge of \$360 plus 12 cents per copy. Company B rents copiers for a monthly charge of \$720 plus 6 cents per copy. What is the number of copies above which Company A's charges are the higher of …
7. ### Pre-Calculus

A local photocopying store advertises as follows. " We charge 14 cents per copy for 150 copies or less,6 cents per copy for each copy over 150 but less than 230, and 3 cents per copy for each copy 230 and above. " Let x be the number …
8. ### Pre-Calculus

A local photocopying store advertises as follows. " We charge 14 cents per copy for 150 copies or less, 6 cents per copy for each copy over 150 but less than 230, and 3 cents per copy for each copy 230 and above. " Let x be the number …
9. ### math

A local photocopying store advertises as follows. " We charge 9 cents per copy for 150 copies or less, 6 cents per copy for each copy over 150 but less than 210 , and 3 cents per copy for each copy 210 and above. " Let x be the number …
10. ### Math

"How many ways are there to arrange some, but not all, of the letters in "Suspension" if at most once copy of each letter can be used?

More Similar Questions