Comments on: An Office supply store sells spiral notebook paper for $2.50 each and notebook paper made of recycled paper of? http://www.proofficesupply.com/blog/an-office-supply-store-sells-spiral-notebook-paper-for-250-each-and-notebook-paper-made-of-recycled-paper-of/ Mon, 13 Feb 2012 09:13:26 +0000 http://wordpress.org/?v=2.7 hourly 1 By: Dr. Nightcall http://www.proofficesupply.com/blog/an-office-supply-store-sells-spiral-notebook-paper-for-250-each-and-notebook-paper-made-of-recycled-paper-of/comment-page-1/#comment-416 Dr. Nightcall Mon, 16 Feb 2009 12:47:08 +0000 http://www.proofficesupply.com/blog/an-office-supply-store-sells-spiral-notebook-paper-for-250-each-and-notebook-paper-made-of-recycled-paper-of/#comment-416 Let s = spiral and r = recycled s+r= 50 2.5s + 2.3r = 118.60 Solve the first equation for either variable. I chose s. s = 50 - r Now substitute into the second. 2.5(50-r) + 2.3r = 118.6 125 - 2.5r + 2.3 = 118.6 -.2r = -6.4 r = 32 s = 18 So 32 recycled and 18 spiral. Substitute these into the second equation to check our work. 2.5(18) + 2.3(32) = 118.60 45 + 73.6 = 118.60 118.60 = 118.60 Let s = spiral and r = recycled
s+r= 50
2.5s + 2.3r = 118.60
Solve the first equation for either variable. I chose s.
s = 50 - r
Now substitute into the second.

2.5(50-r) + 2.3r = 118.6
125 - 2.5r + 2.3 = 118.6
-.2r = -6.4
r = 32 s = 18
So 32 recycled and 18 spiral. Substitute these into the second equation to check our work.

2.5(18) + 2.3(32) = 118.60
45 + 73.6 = 118.60
118.60 = 118.60

]]> By: Lucy http://www.proofficesupply.com/blog/an-office-supply-store-sells-spiral-notebook-paper-for-250-each-and-notebook-paper-made-of-recycled-paper-of/comment-page-1/#comment-415 Lucy Fri, 13 Feb 2009 18:36:50 +0000 http://www.proofficesupply.com/blog/an-office-supply-store-sells-spiral-notebook-paper-for-250-each-and-notebook-paper-made-of-recycled-paper-of/#comment-415 HINT: Write what you know in a table. Variables: s = # of spiral notebook paper sold r = # of recycled notebook paper sold Given: spiral notebook paper for $2.50 each Means: 2.5 * s = 2.5s = value of spiral notebook paper sold Given: notebook paper made of recycled paper for $2.30 Means: 2.3 * r = 2.3r = value of recycled notebook paper sold Given: 50 of these types of paper Means: s + r = 50 Given: sold for a total of $118.60 Means: 2.5s + 2.3r = 118.6 You have 2 equations: s + r = 50 2.5s + 2.3r = 118.6 Solve the first one for s. s + r = 50 s = 50 - r Plug this into the second equation. 2.5s + 2.3r = 118.6 2.5(50 - r) + 2.3r = 118.6 125 - 2.5r + 2.3r = 118.6 125 - 118.6 = 2.5r - 2.3r 125 - 118.6 = 2.5r - 2.3r 6.4 = 0.2r 6.4 / 0.2 = r r = 32 Plug this solved r value into s = 50 - r to solve for s. s = 50 - r s = 50 - 32 s = 18 ANSWER: 18 of the spiral notebook paper and 32 of the recycled notebook paper were sold. HINT: Write what you know in a table.

Variables:
s = # of spiral notebook paper sold
r = # of recycled notebook paper sold

Given: spiral notebook paper for $2.50 each
Means: 2.5 * s = 2.5s = value of spiral notebook paper sold

Given: notebook paper made of recycled paper for $2.30
Means: 2.3 * r = 2.3r = value of recycled notebook paper sold

Given: 50 of these types of paper
Means: s + r = 50

Given: sold for a total of $118.60
Means: 2.5s + 2.3r = 118.6

You have 2 equations:
s + r = 50
2.5s + 2.3r = 118.6

Solve the first one for s.
s + r = 50
s = 50 - r

Plug this into the second equation.
2.5s + 2.3r = 118.6
2.5(50 - r) + 2.3r = 118.6
125 - 2.5r + 2.3r = 118.6
125 - 118.6 = 2.5r - 2.3r
125 - 118.6 = 2.5r - 2.3r
6.4 = 0.2r
6.4 / 0.2 = r
r = 32

Plug this solved r value into s = 50 - r to solve for s.
s = 50 - r
s = 50 - 32
s = 18

ANSWER: 18 of the spiral notebook paper and 32 of the recycled notebook paper were sold.

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