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vleith answered: 2822 problems
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Exponents/143586: This question is from textbook a survey of mathematics
Madeline and Rufus are Chihuahuas and they are never indoors or outdoors at the same time; when one comes in, the other one goes out. Yesterday, Madeline spent 2/3 of the day indoors. How long did Rufus spend indoors? (Hint: they do this 24 hours a day, much to the dismay of their owners.
1 solutions

Answer 104524 by vleith(2825) About Me  on 2008-05-30 07:11:06 (Show Source):
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1/3. since they are never in the same same place, and can only be either inside or outside, then (1 - (2/3) ) = 1/3


Linear-systems/143590: Solve system by the substitution method and indicate wheter each system is independent, inconsistent or dependent
x=1/8y-1
y=1/4x+39
1 solutions

Answer 104523 by vleith(2825) About Me  on 2008-05-30 07:08:58 (Show Source):
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x=1/8y-1
y=1/4x+39
y+=+%281%2F4%29%28%281%2F8%29y+-1%29+%2B+39+
y+=+%281%2F32%29y+-+%281%2F4%29+%2B+39+
32y+=+y+-+8+%2B+1248
31y+=+1240
y+=+40+
x = (40/8)-1 = 4
(4,40)
System is consistent since there is a solution


Rectangles/143591: the lenght of a rectangle is 4 feet less than twice the width. the perimeter is 28 feet. find the length and width fo the rectangle.
1 solutions

Answer 104522 by vleith(2825) About Me  on 2008-05-30 07:03:26 (Show Source):
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Perimeter is the sum of all the sides.
Let w be the width.
L = 2w-4
P = w + l + w + l
28 = w + 2w -4 + w + 2w -4
28 = 6w - 8
36 = 6w
6 = w
l = 12 - 4
l = 8
Does that work?
28 = 12 + 16 check!


Geometry_Word_Problems/143594: This question is from textbook Principles of Math
Two cabins, A and C are located 450m apart on the bank of a river. Across the river from the two cabins is a boathouse at B. Use the information in the diagram to calculate the width of the river. Angle CAB is 70 degrees. Angle BCA is 30 degrees.

1 solutions

Answer 104521 by vleith(2825) About Me  on 2008-05-30 06:59:37 (Show Source):
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See this --> http://en.wikipedia.org/wiki/Law_of_sines
Use the law of sines.
You are given 2 angles, so you can find the third angle (180 - (70+30) )
Now use law of sines to find the distance AB or AC
Once you have AB or AC, use sin and that length to find the width of the river.


Permutations/143571: Please help me solve this extended word problem:
Given the following crcumstances tell if a combination or permutation and solve.
a. Cassandra has seven skirts, five blouses, and ten pair of shoes, how many outfits can she create?
1 solutions

Answer 104517 by vleith(2825) About Me  on 2008-05-30 04:51:36 (Show Source):
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Take a look at this video. There is a problem just voer halfway through that is almost exactly this problem.
http://collabvsl.wetpaint.com/page/Basic+Probability


Geometry_Word_Problems/143596: This question is from textbook Principles of Math
A store sign is 9m high. The maximum length of the ladder is 10m Will the top of the ladder safely reach the sign? The ladder is 2m from the wall and the angle betweeen the ladder and the ground 75.5 degrees. Explain
1 solutions

Answer 104516 by vleith(2825) About Me  on 2008-05-30 04:48:02 (Show Source):
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Yes.
Thw angle where the ladder touches the ground is given as 75.5 degrees. sin is defined as opposite/hypotenuse.
sin%2875.5%29+=+y%2F10
sin%2875.5%29+%2A+10+=+y
+9.68+=+y+


Word_Problems_With_Coins/143545: Hi i have a question that is really baffaling me.Can someone please help me?

A jar of change has $90.15 in it.There are six less dimes than twice the nickels.There are three more quarters than 4 times the amount of nickels.How many nickels,dimes,and quarters are in the jar?(There are no pennies.)Thanks!!
1 solutions

Answer 104464 by vleith(2825) About Me  on 2008-05-29 16:52:54 (Show Source):
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90.15
Let n be the number of nickels
Dimes = 2n - 6 --> d = 2n - 6
Quarters = 4n + 3 --> q = 4n +3

9015 = 5n + 10d + 25q = n + 10*(2n - 6) + 25*(4n +3)
9015 = 5n + 20n - 60 + 100n + 75
9015 = 125n - 15
9000 = 125n
72 = n
d = 144 -6 = 138
q = 291
Does that check?
0.25*291 + 0.1*138 + 0.05* 72 = 90.15


Miscellaneous_Word_Problems/143521: How much Flam would be needed to produce 10 pounds of Flim? When 52 pounds of Flam produce 13 pounds of Flim?
1 solutions

Answer 104448 by vleith(2825) About Me  on 2008-05-29 12:22:24 (Show Source):
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Setup a ratio
52/13 = x/10
then cross multiply to find x


real-numbers/143499: write each equationin standard form y=7/12x+1
1 solutions

Answer 104438 by vleith(2825) About Me  on 2008-05-29 11:03:10 (Show Source):


real-numbers/143500: write each equation in standard form y=7x-5
1 solutions

Answer 104437 by vleith(2825) About Me  on 2008-05-29 11:01:31 (Show Source):
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Given +y=7x-5
standard form is Ax + By = C (where A and B are integers, A is positive)
-7x+%2B+y+=+-5
+7x+-+y+=+5+


Linear-systems/143506: Oh, please help me with this, I do NOT understand this system math....
Solve the following system by substitution.
4x - 2y = 8
2x + 4y =8

1 solutions

Answer 104436 by vleith(2825) About Me  on 2008-05-29 10:58:42 (Show Source):
You can put this solution on YOUR website!
see this --> http://collabvsl.wetpaint.com/page/Solving+Systems+of+Equations

4x - 2y = 8
2x + 4y =8
2x + 4y = 8
2x = 8 -4y
x = (8-4y)/2 use this and sub into the first equation
4x - 2y = 8
4((8-4y)/2) - 2y = 8
16 - 8y - 2y = 8
-10y = -8
y = 4/5
Use this value of y to sub back in and solve for x
x = 12/5
check your answers


Linear-equations/143507: 9x+3y=93
3x-4y=11
1 solutions

Answer 104435 by vleith(2825) About Me  on 2008-05-29 10:54:02 (Show Source):
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See this and let me know if you still cant solve the problem.
http://collabvsl.wetpaint.com/page/Solving+Systems+of+Equations


absolute-value/143508: I am so confused about this question, I don't know where to start. This is how it was typed on the word document.
. Jack was able to travel 30 miles downstream in 2 hours. In returning upstream, it took 3 hours to make the trip. How fast can his boat travel in still water? What was the rate of the river current?



2(r+c)=30--->2r+2c=30-->6r+6c=90
3(r-c)=30---->3r-3c=30--> 6r+6c=60

1 solutions

Answer 104434 by vleith(2825) About Me  on 2008-05-29 10:52:57 (Show Source):
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Minor error is causing you grief
2(r+c)=30--->2r+2c=30-->6r+6c=90
3(r-c)=30---->3r-3c=30--> 6r+6c=60 <-- you changed - to + here
3(r-c)=30---->3r-3c=30--> 6r-6c=60 should be this
Now just use elimination to solve. See here for a video on solving systems of equations. http://collabvsl.wetpaint.com/page/Solving+Systems+of+Equations
6r + 6c = 90
6r - 6c = 60
------------
12r = 150
r = 12.5
r+c = 15
12.5 + c = 15
c = 2.5
Does that check out?


Graphs/143482: how to draw graph for equation Y=6x3
1 solutions

Answer 104427 by vleith(2825) About Me  on 2008-05-29 07:28:35 (Show Source):
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There is really no simple way to do that beyond taking a few points and making a table.
I suggest plugging in x = -3, -2, -1, 0, 1, 2, 3 Solve for Y at each of those values of x. Then plot the points. The shape of the plot will be clear enough with that number of points.
X Y
-3 6*(-3)^3 = -162
-2 6*(-2)^3 = -48
-1 -6
0 0
1 6
2 48
3 162

Make sure your graph scale is large enough allow for the fact that the Y values are growing exponential.


Geometry_Word_Problems/143495: a man stands atop a building. he measures the angle of elevation to the building across the street to be 20 degrees and the angle of depression(to the base of the building) to be 35 degrees. if two buildings are 50 feet apart how tall is the taller building. please show all work and find the solution
1 solutions

Answer 104425 by vleith(2825) About Me  on 2008-05-29 07:22:57 (Show Source):
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You have two right triangles.
Both have an adjacent leg of 50 ft.
Looking up at 20degrees. The opposite leg of the 'upper triangle' can be found by
tan%2820%29+=+opposite%2Fadjacent
0.364+=+opposite%2F50
18.20+=+opposite
Looking down at 35 degrees. The opposite leg of the lower triangle' can be found by
tan%2835%29+=+opposite%2Fadjacent
0.7+=+opposite%2F50
35.01+=+opposite
So the next building is 18.20+%2B+35.01+ft = 53.21ft high


Rational-functions/143465: The view of rectangular box at the right shows three faces of the box. The areas of two of the faces are 30 cm squared and 48 cm squared. The volume of the box is 240 cm cubed. What is the area of the third face?
1 solutions

Answer 104419 by vleith(2825) About Me  on 2008-05-29 06:20:27 (Show Source):
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You are given three pieces of information.
Label the axis on the box w, d and h (for width, depth and height).
Now setup equations for what you 'know'
Volume+=+w%2Ad%2Ah+
Area1+=+w%2Ah+=+30 --> h+=+30%2Fw
Area2+=+h%2Ad+=+48 --> d+=+48%2Fh
Combining the previous two equations yeilds
d+=+48w%2F30
Now plug in the values for d and h into the Volume equation.
Volume+=+w+%2A+d+%2A+h+
240+=+w+%2A+%2848w%2F30%29+%2A+%2830%2Fw%29+
Reduce to get
240+=+48w+
5+=+w
Substitute w=5 back into the earlier equations to get
h+=+30%2F5 = 6
d+=+48%2Fh = 48%2F6 = 8
That's a pretty small box





Length-and-distance/143487: A rectangular field is 260 feet in perimeter.the length is 10 feet more than twice the width.what is the length?
1 solutions

Answer 104418 by vleith(2825) About Me  on 2008-05-29 06:10:09 (Show Source):
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Let the width = w.
The length is given as "10 feet more than twice the width". So l+=+10%2B2w
The perimeter is givenb as 260 feet. You know the perimeter of a rectangle is
P+=+2w+%2B+2l
260+=+2w+%2B+2%2810%2B2w%29+
260+=+2w+%2B+20+%2B+4w+
260+-+20+=+2w+%2B+4w+
240+=+6w+
40+=+w+
Check your answer.
If w = 40 , then length = 10+80 = 90.
Is 2*40 + 2+90 = 260??


test/143488: 7y^2 divided by 2 X 8x divided by 20y
1 solutions

Answer 104417 by vleith(2825) About Me  on 2008-05-29 06:05:42 (Show Source):
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watch this - I bet you can do it yourself afterwards
http://collabvsl.wetpaint.com/page/Simplifying+rational+expressions+using+multiplication+or+division
Let me know if you can't get it after watching


Linear-systems/143489: How to solve 3 unknown with 2 linear equations?
1 solutions

Answer 104416 by vleith(2825) About Me  on 2008-05-29 06:03:10 (Show Source):
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Can't do it. The best you can do is to get down to one varialbe in terms of the other two.


Radicals/143490: I wasnt sure how to insert a radicand, so I used/ to represent the radicand I need help with the problem, thank you in advance!
7/45-2/5

1 solutions

Answer 104415 by vleith(2825) About Me  on 2008-05-29 06:02:07 (Show Source):


logarithm/143336: Use Logarithms to answer the following questions :
1) C = 3.8^2 / 0.943
2) B = cube root of (28.6/0.987)
3) A = (cube root of (39304))/ 136
4) A = square root of ( (16.843)^0 * cube root of(18.8) )
Please help, i need help with these to prepare for an exam.
Thanks
Rebekah
1 solutions

Answer 104305 by vleith(2825) About Me  on 2008-05-28 06:53:57 (Show Source):
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Let's do the first one. Then you can do then next 2
C+=+3.8%5E2+%2F+%280%2F943%29+
Using logs
LogC+=+Log%28%283.8%5E2%29%2F%280.943%29%29+
LogC+=+2%2ALog%283.8%29+-+Log%280.943%29+
LogC+=+1.1596+-++%28-0.0254%29+
LogC+=+1.185
10%5E%28LogC%29+=+10%5E%281.185%29+
C+=+15.31

2 and 3 are much the same
For the last problem, remember that anything raised to the 0 power is "1".
Given A+=+sqrt%28%2816.843%29%5E0+%2A+%2818.8%29%5E%281%2F3%29+%29
A+=+sqrt%281+%2A+%2818.8%29%5E%281%2F3%29+%29
A+=+sqrt%28%2818.8%29%5E%281%2F3%29+%29
A+=+%2818.8%29%5E%281%2F6%29+%29
Which looks like the same problems as above


Circles/143335: Find circumference of circle with a radius of 14 in. Use 22/7 for pi.

1 solutions

Answer 104304 by vleith(2825) About Me  on 2008-05-28 06:46:15 (Show Source):
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C+=+2%2Api%2Ar
given r = 14 inches and pi is apporxiamted as 22/7
C+=+2+%2A+%2822%2F7%29+%2A+14
C+=+88+inches


logarithm/143244: Tutors: Express as a product
logaX^4
and

In y^5
Thank you for the help!!!!
1 solutions

Answer 104240 by vleith(2825) About Me  on 2008-05-27 16:31:02 (Show Source):
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logaX^4 = 4* logaX
ln(y^5) = 5 * ln(y)
See here --> Look at rule 3 http://www.purplemath.com/modules/logrules.htm


Trigonometry-basics/143235: I am completely confused regarding trig, the beginner trig in involving right triangles:
Sin: opposite leg/ hypotenuse
Cos: adjacent leg/ hypotenuse
Tan: adjacent leg/opposite leg
Is this correct?
How do you know what leg is adjacent?
What happens when you have a angle but you need to find a leg number? Do you use 'sin-1'?
1 solutions

Answer 104235 by vleith(2825) About Me  on 2008-05-27 16:00:38 (Show Source):
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Tangent = opposite/adjacent
See here for a good picture --> http://www.grc.nasa.gov/WWW/K-12/airplane/sincos.html
When thinking about sine, cosine and tangent, one has to think about which vertex of the triangle you are referencing. Assume you pick one vertex, then the adjacent leg is the one that 'touches' your vertex. The hypotenuse is always the 'long side'. make sense?
When you have an angle, and also one of the sides (but not a second side), you setup the ratios as you nothed above, and then use your calculator to find the sine or cosine ro tangent of the angle. The cross multiply to find the unknown side.


Trigonometry-basics/143157: Solve for X: (3x/x+2)+(7/x-2)=3
1 solutions

Answer 104233 by vleith(2825) About Me  on 2008-05-27 15:33:02 (Show Source):


Geometry_proofs/143178: parallelogram abcd is not a rectangle the points of a b c and d are (-2,2) (6,5) (4,0) (-4,-3) prove that paralleogram is not a rectangle
1 solutions

Answer 104230 by vleith(2825) About Me  on 2008-05-27 15:16:45 (Show Source):
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All you need to do is prove the line segments that create one of the vertex are not at right angles.
Find the slope of one side segment, then find the slope of the segment that intersects at that vertex. Then show the products of those slopes is not equal to -1.
If you can show that, then the shape cannot be a rectangle.


Subset/143197: This question is from textbook Survey of Math w/ Apllications
Could you help me solve this px
6. (3 pts) Given U = {l, m, n, o, p, q, r, s, t, u, v, w}, A = {l, m, n, o, p, q}, B = {n, o, r, s, v, w}, and C = {l, m, p, q, r, t}, find (A′ U C′) ∩ B′.
1 solutions

Answer 104229 by vleith(2825) About Me  on 2008-05-27 15:12:23 (Show Source):
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A' is everything in U that is not in A --> A'={r,s,t,u,v,w}
C' is everything in U not in C --> C' = {n,o,s,u,v,w}
Union of A' and C' is everything in either one A' U C' ={n,o,r,s,t,u,v,w}
Now you figure out B'
Then take the intersection og B' and A' U C' (get the elements that are common to both B' and A'U C')
Ping me if you dont understand


Square-cubic-other-roots/143203: 7times the square root of 7 mnus 2 times the squre root of 7
1 solutions

Answer 104228 by vleith(2825) About Me  on 2008-05-27 15:06:50 (Show Source):
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7+%2A+sqrt%287%29++-+2%2Asqrt%287%29+
Let sqrt(7) be x
7+%2Ax+-+2%2Ax+
Can you solve that one? i bet you can.
5x
but x = sqrt(7)
5%2Asqrt%287%29
The sqrt(7) adds and subtracts just like any other number ... just more difficult to get your mind around what the value is. For this problem, we don't care what the sqrt(7) is. We just let it ride !


Linear-systems/143212: This question is from textbook algebra and trigonometry
please help me solve problem number 27 of page 152, Review exercises. thankyou.
1 solutions

Answer 104227 by vleith(2825) About Me  on 2008-05-27 14:57:29 (Show Source):
You can put this solution on YOUR website!
You gotta be kidding. Do you think we own your math book? If you want help, you need to assume what we 'know' is what you provide to us.


Money_Word_Problems/143231: Hi, another question from the GRE math test prep.
A group can charter a particular aircraft at a fixed total cost. If 36 people charter the aircraft rather than 40 people, then the cost per person is greater by $12. What is the cost per person if 40 people charter the aircraft?
Thank you!!
Lauren
1 solutions

Answer 104226 by vleith(2825) About Me  on 2008-05-27 14:55:51 (Show Source):
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let the total cost = C
The person cost is :
Let the cost per person with 40 = c
The cost per person at 36 = c+ 12
Total cost is the same:
40c+=+36%28c+%2B+12%29
40c+=+36c+%2B+432+
4c+=+432+
c+=+108+
Check yor answer. does 40*108 = 36(120)?? as they say in fargo 'you betcha'


logarithm/143204: 3^x=40
e^0.04t=1500
please help me solve these... if possible...i need good step by step process

1 solutions

Answer 104225 by vleith(2825) About Me  on 2008-05-27 14:46:26 (Show Source):
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Use logs
Given: 3%5Ex=40
Take the log of both sides
log%283%5Ex%29+=+log%2840%29
When using logs, if the term inside parens is raised to a power, then your can 'bring the power down' as a multiplier.
x+%2A+log%283%29+=+log%2840%29+
Now get out your handy calculator and find log(3) and log(40)
x+%2A+%280.47712%29+=+1.602
Now solve for x as a one step algebra simplification
x+=+3.3576
Finally, check your answer using a calculator. Does 3^3.3576 = 40? Close enough!
For the second problem, use logs again. Except this time, use natural log (ln)
Given: e%5E%280.04t%29=1500
Take the ln of both sides
ln%28e%5E%280.04t%29%29+=+ln%281500%29+
The ln of a power of e, it just the power.
0.04t+=+ln%281500%29+
Whip out your calculator and find ln(1500) (somebody help that man!)
0.04t+=+7.313
+t+=+182.83
Check your answer using the calculator. Does it check out? You bet it does,