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Evaluation_Word_Problems/68114: Allen bought 20 stamps at the post office in 37¢ and 20¢ denominations. If the total cost of the stamps was $7.06, how many 37¢ stamps did Allen buy? 1 solutions
Answer 48473 by checkley71(8403) on 2007-01-26 22:24:15 (Show Source):
You can put this solution on YOUR website!X+Y=20 X BEING THE NUMBER OF $.37 & Y BEING THE $.20 STAMPS.
X=20-Y
.37X+.20Y=7.06
.37(20-Y)+.20Y=7.06
7.40-.37Y+.20Y=7.06
-.17Y=7.06-7.40
-.17Y=-.34
Y=-34/-17
Y=2 NUMBER OF $.20 STAMPS.
X+2=20
X=20-2
X=18 NUMBER OF $.37 STAMPS.
PROOF
.37*18+.20*2=7.06
6.66+.40=7.06
7.06=7.06
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Triangles/68177: Triangle ABC is a right triangle. If side AC=5 and side BC=6, What is the measure of side AB? 1 solutions
Answer 48466 by checkley71(8403) on 2007-01-26 22:02:16 (Show Source):
You can put this solution on YOUR website!IF AB IS THE HYPOTENUSE THEN
AB^2=5^2+6^2
AB^2=25+36
AB^2=61
AB=SQRT61
AB=7.81
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IF BC IS THE HYPOTENUSE THEN
6^2=5^2+AB^2
36=25+AB^2
36-25=AB^2
9=AB^2
AB=SQRT9
AB=3
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Linear-equations/68090: I am helping my 13 year old with his homework. Please tell me what slope is and how it is measured in general. We are using an Egyptian pyramid as a model.
Thank you ! 1 solutions
Answer 48380 by checkley71(8403) on 2007-01-25 21:44:57 (Show Source):
You can put this solution on YOUR website!WHAT YOU NEED TO DO IF YOU ARE USING A PYRAMID THEN PLOT TWO OF THE POINTS (BASE & TOP POINT) ON A GRAPH THUS (0,0) (5,4)
THE SLOPE IS CALCULATED USING
(Y2-Y1)/(X2-X1)
(4-0)/(5/0)
4/5 IS THE SLOPE OFF A LINE BETWEEN THESE TWO POINTS OR THE SLOPE OF THE SIDES OF THE PYRAMID.
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Money_Word_Problems/68087: Jack invested $8000, part at 10% and part at 15%. If the total interest at the end of the year is $900, how much did he invest at 10%?
a)$7000
b)$5000
c)$6000
d)$4000 1 solutions
Answer 48378 by checkley71(8403) on 2007-01-25 21:40:09 (Show Source):
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Linear-systems/68085: Find the slope of any line perpendicular to the line through points(3, 2) and (5, 6).
a)4
b)-4
c)1/4
d)-1/4
Any help would be great, thanks. 1 solutions
Answer 48376 by checkley71(8403) on 2007-01-25 21:33:49 (Show Source):
You can put this solution on YOUR website!the slope of the line between these 2 points is
(6-2)/(5-3)
4/2=2 for the slope.
therefore a line perpendicular has to have a slope that is the negatiuve reciprical of this slope which would be -1/2
don't see (-1/2) as one of the answers.
are you sure you have the correct points?
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Linear-systems/68082: Determine which two equations represent parallel lines.
a)y = 3x - 5
b)y = -3x + 5
c)y = 3x + 3
d)y = -1/3x -5
Any help would be greatful. 1 solutions
Answer 48375 by checkley71(8403) on 2007-01-25 21:26:56 (Show Source):
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Quadratic_Equations/68077: Here is another problem that I have posted within the past 2 days that I am having trouble with setting up. If someone could give me a little hint, I would appreciate it. Thanks.
A garden area is 30 ft long and 20 ft wide. A path of uniform width is set around the edge. If the remaining garden area is 400 ft2, what is the width of the path? Give your answer in decimal form, rounded to the nearest thousandth. 1 solutions
Answer 48374 by checkley71(8403) on 2007-01-25 21:24:44 (Show Source):
You can put this solution on YOUR website!(30-2X)(20-2X)=400
600-40X-60X+4X^2=400
4X^2-100X+600-400=0
4X^2-100X+200=0
X^2-25X+50=0
using the quadratic equation we get
x=(-b+-sqrt[b^2-4ac])/2a
x=(25+-sqrt[-25^2-4*1*50])/2*1
x=(25+-sqrt625-200])/2
x=(25+-sqrt425)/2
x=(25+-20.6155)/2
x=(25+20.6155)/2
x=45.6155
x=(25-20.6155)/2
x=4.3845/2
x=2.192 answer for the width of the path.
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IF YOU DRAW A DIAGRAM OF THE PROBLEM (WHICH I ALWAYS RECOMMEND) YOU'LL SEE THAT THE RECTANGLE INSIDE ANOTHER RECTANGLE WITH THE OUTSIDE DIMENTIONS OF 20 & 30 FT
YOU'LL SEE THAT THE INNER RECTANGLE LENGTH IS 30 & 20 -2 TIMES THE BORDER (X) THUS THE TERMS 30-2X & 20-2X TO DESCRIBE THE INNER RECTANCLE.
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Geometry_Word_Problems/68072: This question is from textbook Geometry
A zip lane is a taut rope or cable that you can ride down on a pulley the zip line at the right goes from a 9 feet tower to a 6 feet tall tower. The towers are 20 feet apart. What is the slope of the zip lane? 1 solutions
Answer 48371 by checkley71(8403) on 2007-01-25 21:08:12 (Show Source):
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Quadratic_Equations/68069: I have asked this question within the past two days without a response. I am having a tough time figuring out how to set this problem up. Once I know how to set it up and why, I can probably solve the equation. I hope someone out there can help me with this one, please.
Find two consecutive positive integers such that the sum of their squares is 85. [You must use algebra to solve this, setting up an equation with a variable, and using algebra to solve for the variable.] 1 solutions
Answer 48370 by checkley71(8403) on 2007-01-25 21:02:40 (Show Source):
You can put this solution on YOUR website!let x^2 be the first number & (x+1)^2 the next number
x^2+(x+1)^2=85
x^2+x^2+2x+1=85
2x^2+2x+1-85
2x^2+2x-84=0
x^2+x^2-42=0
(x+7)(x-6)=0
x-6=0
x=6 answer for the first number
6+1=7 for the next number.
proof
6^2+7^2=84
36+49=84
84=84
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absolute-value/67919: This question is from textbook Algebra:Structure and Method
If I increase my usual driving speed by 10 km/h, I can drive the 255 km to Nashviille in 24 minutes less than usual. How fast do I usually drive? 1 solutions
Answer 48307 by checkley71(8403) on 2007-01-24 20:33:28 (Show Source):
You can put this solution on YOUR website!255/x=255/(x+10)+.4
255/x=(255+.4x+4)/(x+10)
255/x=(259+.4x)/(x=10)
255(x+100=x(259+.4x)/(x+10)
255x+2550=259x+.4x^2
.4x^2+4x-2550=0
(.4x-30)(x+85)=0
.4x-30=0
.4x=30
x=30/.4
x=75 km/h is the normal speed
75+10=85 km/h is the faster trip speed
proof
255/75=255/85+.4
3.4+3+.4
3.4=3.4
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Money_Word_Problems/67821: At the movies tickets for adults cost $5.50 and tickets for children cost $3.50. How many of each kind of ticket was purchased if 21 tickets were bought for $83.50? 1 solutions
Answer 48222 by checkley71(8403) on 2007-01-23 22:02:40 (Show Source):
You can put this solution on YOUR website!C+A=21 & 550*A+350*C=8350
C=21-A
550A+350(21-A)=8350
550A+7350-350A=8350
200A=8350-7350
200A=1000
A=1000/200
A=5 ANSWER FOR NUMBER OF ADULT TICKETS SOLD
21-5=16 ANSWER FOR CHILDREN TICKETS SOLD
PROOF
550*5+350*16=8350
2750+5600=8350
8350=8350
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Mixture_Word_Problems/67819: A liter of cream has 9.2% butterfat. How much skim milk containing 2% butterfat should be added to the cream to obtain a maxture of 6.4% butterfat? 1 solutions
Answer 48219 by checkley71(8403) on 2007-01-23 21:53:50 (Show Source):
You can put this solution on YOUR website!1*.092+.02X=.064(1+X)
.092+.02X=.064+.064X
.02X-.064X=.064-.092
-.044X=-.028
X=-.028/-.044
X=.6363 LITERS OF 2% IS NEEDED
PROOF
.092+.02*.6363=.064(1.6363)
.092+.012726=.10472
.10472=.10472
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Linear_Algebra/67792: A farmer normally plows a rectangular field 80ft by 120 ft. This year the farmer wants to expand the area of the field by 20%, by extending the width and length of the plowed area an equal amount. How much wider and longer should the farmer plow the field to obtain a 20% increase in area? 1 solutions
Answer 48215 by checkley71(8403) on 2007-01-23 21:42:40 (Show Source):
You can put this solution on YOUR website!CURRENT AREA=80*120=9600
TO INCREASE THIS AREA BY 20% IT MUST BE 9600*1.2=11520
THUS (80+X)(120+X)=11520
9600+120X+80X+X^2=11520
X^2+200X+9600-11520=0
X^2+200X-1920=0
USING THE QUADRATIC EQUATION WE GET
X=(-B+-SQRT[B^2-4AC])/2A
X=(-200+-SQRT[200*200-4*1*-1920])/2*1
X=(-200+-SQRT[40000+7680])/2
X=(-200+-SQRT47680])/2
X=(-200+-218.3578)/2
X=-200+218.3578)/2
X=18.3578/2
X=9.17875 ANSWER.
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Graphs/67796: Solve by graphing.
x + y = 3
x - y = 1
I did:
x + y = 3 y = -x + 3 m = -1, 6 = 3
x - y = 1 -y = -x + 1 m = -1, 6 = 1
on my graph they coincided with each other instead of intersecting which is how the answer reads. (2,1)
Where did I go wrong?
Thanks a lot. Kyle 1 solutions
Answer 48211 by checkley71(8403) on 2007-01-23 21:27:13 (Show Source):
You can put this solution on YOUR website!X+Y=3
Y=-X+3
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X-Y=1
-Y=-X+1
Y=X-1 this is where you made your mistake. you neglected to change -y to +y by multiplying the equation by -1.
also you have a 6 instead of a y in your answer.
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 (graph 300x200 pixels, x from -6 to 5, y from -5 to 5, of TWO functions y = -x +3, y = x -1).
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Geometry_Word_Problems/67815: Given the formula P=-x/2 +75. Find the unit price
if seven items are sold. 1 solutions
Answer 48207 by checkley71(8403) on 2007-01-23 21:10:01 (Show Source):
You can put this solution on YOUR website!X REPRESENTS THE NUMBER OF ITEMS SOLD
THUS REPLACING X BY 7 IN THIS CASE WE GET
P=-7/2+75 NOW WE DIVIDE -7 BY 2 AND GET -3.5
P=-3.5+75 NOW WE SUBTRACT THE 3.5 FROM 75 AND WE GET
P=71.5 WHICH IS THE PRICE WHEN 7 UNITS ARE SOLD.
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