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Mathtut answered: 3667 problems
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percentage/192284: How much would you owe after making the down payment for the cassette
player?
Cassette player:15%, 18$, Total Cost $ ?
Thanks for all help!
1 solutions

Answer 144348 by Mathtut(3670) About Me  on 2009-04-21 02:32:56 (Show Source):
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if 15% of the total cost say x is 18 dollars then total cost is
:
.15x=18
:
x=120 dollars


test/192299: One pipe can fill a tank in 20min, while another takes 30min to fill the same tank. How long would it take the two pipes together to fill that tank?
1 solutions

Answer 144344 by Mathtut(3670) About Me  on 2009-04-21 01:38:28 (Show Source):
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1/20 of the pipe per min
:
1/30 of the pipe per min
:
together
:
(1/20+1/30)t=1
:
(3/60+2/60)t=1
:
(5/60)t=1
:
t=60/5=12 minutes


Coordinate-system/192311: This question is from textbook Intermediate Algebra an Applied Approach
Which of the following equations represents a line l that goes through (–3,–1) and (–1,4)?
My work is : y=5/2 x -1 ?
1 solutions

Answer 144343 by Mathtut(3670) About Me  on 2009-04-21 01:32:16 (Show Source):
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-1-4/-3+1=5/2
:
y-4=(5/2)(x+1)
:
y-4=(5/2)x+5/2
:
2y-8=5x+5
:
5x-2y=-13


Polygons/192283: determine the measure of the interior angles for each of the regular polygons in the table. regular polygans Measure of interior angles
triangle 60 degrees
square
pentagon
hexagon
heptagon



thank you

1 solutions

Answer 144342 by Mathtut(3670) About Me  on 2009-04-21 01:29:08 (Show Source):
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http://www.coolmath.com/reference/polygons.html


Percentage-and-ratio-word-problems/192303: Lisa will make punch that is 25% fruit juice by adding pure fruit juice to a 2-liter mixture that is 10% pure fruit juice. How many liters of pure fruit juice does she need to add?
1 solutions

Answer 144341 by Mathtut(3670) About Me  on 2009-04-21 01:16:17 (Show Source):
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.1(2)+x=.25(2+x)
:
.2+x=.5+.25x
:
.75x=.3
:
x=.4 liters


Geometry_Word_Problems/192267: Find the volume to the nearest tenths, of a cone with diameter 3 feet and height 1.5 feet.
1 solutions

Answer 144306 by Mathtut(3670) About Me  on 2009-04-20 21:33:32 (Show Source):
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V=%281%2F3%29%28pi%29r%5E2h
:
V=%281%2F3%29%28pi%29%281.5%29%5E2%2A%281.5%29
:
V=%283.375%28pi%29%29%2F3
:
V=3.5cu ft(nearest tenth)%28pi%29=3.14


Geometry_Word_Problems/192235: From the top of a 200-foot cliff, the angle of depression to a boat offshore is 15 degrees. To the nearest foot, how far is the boat from the base of the cliff?
1 solutions

Answer 144295 by Mathtut(3670) About Me  on 2009-04-20 20:43:47 (Show Source):
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opposite over ajacent problem so we will deal with tangent
:
tan 15=200/x........where x is the distance from the boat to the base of cliff
:
0.26794919243112 x=200
:
x=746 ft (the nearest foot)


Linear-systems/192256: This question is from textbook Intermediate Algebra
An office has some 20 cent stamps and some 28 cent stamps. All together the office has 140 stamps for a total value of $31.20. How many of each stamp does the office have?
my try:
Stamps Number Value Total Value
20 cent x .20 .20x
28 cent 140 -x .28 .28(140-x)
.20x + .28(140-x) = 31.20
.20x + 39.20 - .28x = 31.20
.08x + 39.20 = 31.20
-.08x = -8.00
x = 1
WRONG? What am I doing wrong?? Help!

1 solutions

Answer 144294 by Mathtut(3670) About Me  on 2009-04-20 20:38:51 (Show Source):
You can put this solution on YOUR website!
let the number of 20 cent and 28 cent stamps by x and y respectively
:
x+y=140........eq 1
.2x+.28y=31.2..eq 2
:
rewrite eq 1 to x=140-y and plug it into eq 2
:
.2(140-y)+.28y=31.2
:
28-.2y+.28y=31.2
:
.08y=3.2
:
y=40 (28 cent stamps)
:
x=140-y=140-40=100 (20 cent stamps)


Surface-area/192257: This question is from textbook houghton miffilin mathematics practice workbook
what is the surface area of a cube with sides the length of 4ft

1 solutions

Answer 144293 by Mathtut(3670) About Me  on 2009-04-20 20:33:32 (Show Source):
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surface AREA=6(4*4)=96 sq ft


Polynomials-and-rational-expressions/192255: solve t2 + t=0
1 solutions

Answer 144292 by Mathtut(3670) About Me  on 2009-04-20 20:32:21 (Show Source):
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t%28t%2B1%29=0
:
t=0 or t=-1


Probability-and-statistics/192226: P(G) = 0.5, P(H) = 0.6, and P(G|H′) = 0.25. Find P(G and H'), P(G or H), and P(P(G|H). I know that the answers are 1/10, 7/10, and 2/3 respectively, I'm just not sure how to get them. Thank you!!
1 solutions

Answer 144290 by Mathtut(3670) About Me  on 2009-04-20 20:30:43 (Show Source):
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The first problem is:
:
since P(H)=.6 we know that P(H')=.4
:
P(G|H')=P(G and H')/P(H')
:
.25=P(G and H')/.4)---->P(G and H')=.4(.25)=.1 or 1/10
:


Numbers_Word_Problems/192238: This question is from textbook Algebra 1
The additive inverse of a number divided by 12 is the same as one less than three times its reciprocal. Find the number.
1 solutions

Answer 144286 by Mathtut(3670) About Me  on 2009-04-20 20:18:17 (Show Source):
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let the number be x
:
-x%2F12=3%281%2Fx%29-1
:
-x=%2836%2Fx%29-12
:
-x=%2836-12x%29%2Fx
:
x%5E2-12x%2B36=0
:
%28x-6%29%28x-6%29=0
:
x=6


Rational-functions/192220: can you please show me how to do this problem? %28q%29%2F%28m%29=%282V%29%2F%28b%5E2%29%28r%5E2%29 solve for B.
1 solutions

Answer 144284 by Mathtut(3670) About Me  on 2009-04-20 20:06:30 (Show Source):
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qb%5E2r%5E2=2Vm after cross multiplication
:
b%5E2=%282Vm%2Fqr%5E2%29
:
b=sqrt%28%282Vm%2Fqr%5E2%29%29


Trigonometry-basics/192204: help
1 solutions

Answer 144283 by Mathtut(3670) About Me  on 2009-04-20 20:03:15 (Show Source):
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tutors have NO access to problem....please post actual problem...thanks Mathtut


real-numbers/192214: In a local area the government intends to reduce the coyote population by 10% each year. If the coyote population is now estimated to be 3,000, how many coyotes will remain after 3 years?
1 solutions

Answer 144282 by Mathtut(3670) About Me  on 2009-04-20 20:02:15 (Show Source):
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3000-3000(.1)=2700
:
2700-2700(.10=2430
:
2430-2430(.10)=2187


Rational-functions/192216: m/F=1/a;F
1 solutions

Answer 144280 by Mathtut(3670) About Me  on 2009-04-20 19:53:31 (Show Source):


Polynomials-and-rational-expressions/192218: Please help me with this question:
15x^2+x-6
1 solutions

Answer 144279 by Mathtut(3670) About Me  on 2009-04-20 19:52:08 (Show Source):


Rational-functions/192219: solve for F. %28m%29%2F%28F%29=+%281%29%2F%28a%29
1 solutions

Answer 144278 by Mathtut(3670) About Me  on 2009-04-20 19:50:17 (Show Source):
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cross multiply to get F=ma


Quadratic_Equations/192229: Please help.
Write without exponents.
4^3/2
1 solutions

Answer 144277 by Mathtut(3670) About Me  on 2009-04-20 19:49:16 (Show Source):


Coordinate-system/192230: This question is from textbook Prentice Hall Mathematics Algebra I
Graph each function. Label the axis of symmetry, the vertex and the y-intercept.
y = x^2 - 6x + 4

1 solutions

Answer 144276 by Mathtut(3670) About Me  on 2009-04-20 19:47:55 (Show Source):
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y=%28x%5E2-6x%2B9%29-9%2B4
:
y=%28x-3%29%5E2-5
:
vertex is (3,-5)
:
y intercept is found by setting x to zero y=0%5E2-6%280%29%2B4=4: (0,4)
:
axis of symmetry is x=3
:
graph%28300%2C300%2C-10%2C10%2C-10%2C10%2Cx%5E2-6x%2B4%29


Quadratic-relations-and-conic-sections/192231: Please help.
The area of a trapezoid is given by
A=1/2h (a+b),
where h is the height of the trapezoid and a and b are the lengths of the upper and the lower base, respectively.
solve for a
1 solutions

Answer 144275 by Mathtut(3670) About Me  on 2009-04-20 19:44:33 (Show Source):


Geometry_Word_Problems/192234: Find the length to the nearest tenth, of a diagonal of a square whose sides are 10 centimeters long.
1 solutions

Answer 144274 by Mathtut(3670) About Me  on 2009-04-20 19:43:05 (Show Source):
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if each side is 10 cm the diagonal is
:
c%5E2=10%5E2%2B10%5E2
:
c%5E2=200
:
c=sqrt%28200%29=14.1 cm


Graphs/192237: a line in the Cartesian plane passes through the points (-2,4) and (2,-1). what is the rise and the run of the line? I got run is4 and rise is 5 is it corect?
1 solutions

Answer 144272 by Mathtut(3670) About Me  on 2009-04-20 19:40:12 (Show Source):
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rise is -1-4=-5 for which the run would be 2-(-2)=4 or the rise is 4-(-1)=5 for which the run is -2-2=-4
:
in both cases the slope is -5/4


Quadratic_Equations/192242: 12x^2 - 6x = 0
1 solutions

Answer 144270 by Mathtut(3670) About Me  on 2009-04-20 19:36:45 (Show Source):
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6x%282x-1%29=0
:
x=0 or x=1/2


Quadratic_Equations/192114: Give the usual ax^2+bx+c form of the quadratic function which has a= 1, and has two zeros z= -5 and z= 3
1 solutions

Answer 144240 by Mathtut(3670) About Me  on 2009-04-20 16:26:47 (Show Source):


Percentage-and-ratio-word-problems/192178: A lawyer bills her clients $300 per hour of service. If a client's case requires 17 hours to complete, use a proportion to calculate how much the client will owe the lawyer (excluding tax).
1 solutions

Answer 144226 by Mathtut(3670) About Me  on 2009-04-20 15:58:03 (Show Source):
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the proportion is 300 to 1(hour equal x to 17(hours)....where x is the amount owed
:
300%2F1=x%2F17
:
x=300(17)=$5100.....after cross multiplication
:


Linear-systems/192182: Please help me solve...
A women has $7000,part is invested for one year paying 7% interest and the remaining amount in a fund paying 9%. After a year total interest on the 2 investments is $540. How much is invested at each rate?
1 solutions

Answer 144224 by Mathtut(3670) About Me  on 2009-04-20 15:55:17 (Show Source):
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let amounts invested at 7% and 9% be x and y respectively
:
x+y=7000...........eq 1
.07x+.09y=540......eq 2
:
rewrite eq 1 to x=7000-y and plug this into eq 2
:
.07(7000-y)+.09y=540
:
490-.07y+.09y=540
:
.02y=50
:
y=2500 dollars invested at 9%
:
x=7000-y=7000-2500=4500 dollars invested at 7%


Equations/192161: I home school and I am stuck on a problem.
all the information the directions give me is "solve each equation"
The worksheet is on radical equations' graphs, and complex numbers
Please help me solve this equation:
(2x-3)^2=-24
1 solutions

Answer 144196 by Mathtut(3670) About Me  on 2009-04-20 14:14:15 (Show Source):
You can put this solution on YOUR website!
%282x-3%29%282x-3%29=-24
:
4x%5E2-6x-6x%2B9=-24
:
4x%5E2-12x%2B36=0
:
4%28x%5E2-3x%2B9%29=0
:
Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 1x%5E2%2B-3x%2B9+=+0) has the following solutons:

x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca

For these solutions to exist, the discriminant b%5E2-4ac should not be a negative number.

First, we need to compute the discriminant b%5E2-4ac: b%5E2-4ac=%28-3%29%5E2-4%2A1%2A9=-27.

The discriminant -27 is less than zero. That means that there are no solutions among real numbers.

If you are a student of advanced school algebra and are aware about imaginary numbers, read on.


In the field of imaginary numbers, the square root of -27 is + or - sqrt%28+27%29+=+5.19615242270663.

The solution is , or
Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B-3%2Ax%2B9+%29



Trigonometry-basics/192147: This question is from textbook
Find the vertex, focus and directrix of the parabola. [NOTE: fractions must be reduced and mixed numbers have to be reported as improper fractions]
y = x2 - 20x + 10
1 solutions

Answer 144194 by Mathtut(3670) About Me  on 2009-04-20 14:09:32 (Show Source):
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y=%28x%5E2-20x%2B100%29-100%2B10
:
y=%28x-10%29%5E2-90
:
vertex is at (10,-90)
:
focus is at (10,-90 + 1/4) (10,89 3/4)(10,359/4)
:
directrix is at y=-90-1/4 =-90 1/4.....y=-361/4


Linear-systems/192157: HAVING A 1) UNIQUE SOLUTION 2)AN INFINITE NUMBER OF SOLUTIONS 3)NO SOLUTION
1 solutions

Answer 144192 by Mathtut(3670) About Me  on 2009-04-20 13:56:46 (Show Source):
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what is the problem????


Functions/192158: Find the domain of f(x) = 5x+1/x^2+5x-14
1 solutions

Answer 144191 by Mathtut(3670) About Me  on 2009-04-20 13:55:38 (Show Source):
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%28x%5E2%2B5x-14%29=0
:
%28x-7%29%28x%2B2%29=0
:
x=7 or -2
:
the domain is all reals except 7 and -2. This would make the denominator equal to zero. the denominator cannot be zero or equation is undefined