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Recent problems solved by 'rfer'

rfer answered: 2688 problems
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Rectangles/241177: the width of a rectangle is fixed at 11 cm. What lengths will make the perimeter greater than 96 cm?
1 solutions

Answer 176686 by rfer(2688) on 2009-11-20 22:45:51 (Show Source):

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96-22=74
74/2>37 cm

Expressions-with-variables/241204: intermediate algebra
Find the missing coordinate
(-3,_____)is a solution of y=4-3x
1 solutions

Answer 176685 by rfer(2688) on 2009-11-20 22:42:38 (Show Source):

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y=4-3x
y=4-3*-3
y=4+9
y=13
(-3,13)

Angles/241206: find the measure of the complement of a 11 degree angle
1 solutions

Answer 176683 by rfer(2688) on 2009-11-20 22:39:43 (Show Source):

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90-11=79 degrees

Functions/241258: how long will it take for the population of a certain country to double if its annual growth rate is 3.3%? round to the nearest year.

i got 21 and 9 years
my freind got 61 and 1
which is correct? :)
1 solutions

Answer 176681 by rfer(2688) on 2009-11-20 22:35:16 (Show Source):

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Just using the rule of 72, I get 21.8 yrs.
That methode is not exact, but close.

Triangles/241252: The measure of one angle of a triangle is 28 more than the measure of the smallest angle of the triangle. The measure of the third angle is twice the measure of the smallest angle. Find all measures.
1 solutions

Answer 176678 by rfer(2688) on 2009-11-20 22:29:12 (Show Source):

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x+x+28+2x=180
4x+28=180
4x=152
x=38 degrees
x+28=66 degrees
2x=76 degrees

Angles/241142: The ratio of the measure of two complimentary angles is 1:5. What are the measures of the angles?
1 solutions

Answer 176627 by rfer(2688) on 2009-11-20 17:29:41 (Show Source):

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x+5x=90
6x=90
x=15 degrees
5x=75 degrees

Percentage-and-ratio-word-problems/241196: lucy earns 21% less than her husband. together, they make $109,675 per year. what is lucy's annual salary?
1 solutions

Answer 176626 by rfer(2688) on 2009-11-20 17:25:49 (Show Source):

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x+.79x=109675
1.79x=109675
x=$61,270.95 husband
.79x=$48,404.05 Lucy

Travel_Word_Problems/241179: if jake runs 18 miles in 3 hour, what was his speed
1 solutions

Answer 176625 by rfer(2688) on 2009-11-20 17:21:16 (Show Source):

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r=D/t
r=18/3
r=6 mph

Coordinate-system/240514: How do I figure out how to graph the problem f(x)=2x-3
1 solutions

Answer 176252 by rfer(2688) on 2009-11-18 20:53:19 (Show Source):

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f(x)=y (same thing)
y=mx+b
m=slope=2 (one right, two up)
b=y int=-3
(0,-3)

Travel_Word_Problems/240572: if d=rt,and if r=60 and t=4,what does d equal?
1 solutions

Answer 176251 by rfer(2688) on 2009-11-18 20:50:24 (Show Source):

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D=rt
D=60*4
D=240

Divisibility_and_Prime_Numbers/240488: What are the correct steps to answer this problem 52 divided by 323.18
1 solutions

Answer 176250 by rfer(2688) on 2009-11-18 20:49:08 (Show Source):

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52/323.18=0.16
when dividing the problem becomes 5200 divided by 32318.

Proportions/240517: What is 14.6=k over 2.5?
1 solutions

Answer 176248 by rfer(2688) on 2009-11-18 20:45:58 (Show Source):

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14.6=k/2.5
multiply by 2.5
36.5=k

Proportions/240528: pao spent $140 of his paycheck and put the remaining $20 in his savings account. If the number of dollars he spends is proportional to the number he saves, how much of a $156-paycheck will he put into savings
1 solutions

Answer 176247 by rfer(2688) on 2009-11-18 20:43:37 (Show Source):

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20/140:x/156
140x=3120
x=$22.29

Money_Word_Problems/240567: Ms. Kork sold her car for $8,700.
This was $100 more than two fifths
of what she had paid for the car
originally. How much had Ms. Kork
paid for the car?
1 solutions

Answer 176244 by rfer(2688) on 2009-11-18 20:38:33 (Show Source):

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(8700-100)/.4=$21,500

Angles/240533: An isocelles triangle has 2 50 degree angles.what is the measure of the third angle?explain
1 solutions

Answer 176242 by rfer(2688) on 2009-11-18 20:34:37 (Show Source):

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80 degrees
triangle angles total 180 degrees

percentage/240552: Briana took a major test on the 5 oceans and 7 continents of the world. She got 16 out of 20 questions correct on the test.
What was her percentage of correct answers?
1 solutions

Answer 176240 by rfer(2688) on 2009-11-18 20:31:08 (Show Source):

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16/20=.8=80%

Exponential-and-logarithmic-functions/240558: What is 7 to the 4th power?
what is 10 to the 6th power?
1 solutions

Answer 176237 by rfer(2688) on 2009-11-18 20:29:15 (Show Source):

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2,401
1,000,000

Numeric_Fractions/240267: (Factor) which of the folowing is a factor of x2 - 5x -6?
1 solutions

Answer 176110 by rfer(2688) on 2009-11-18 11:12:32 (Show Source):

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x^2-5x-6
(x-6)(x+1)

Equations/240283: hello my name is anthony and i need help with this problem cuz i am new at this and so here it is and explain it the best way you can step by step?

5(2x+3)=4(x-1)+1
1 solutions

Answer 176107 by rfer(2688) on 2009-11-18 11:08:12 (Show Source):

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5(2x+3)=4(x-1)+1
10x+15=4x-4+1
subtract 15
10x+15-15=4x-4+1-15
10x=4x-18
subtract 4x
10x-4x=4x-4x-18
6x=-18
divide by 6
6x/6=-18/6
x=-3

Linear-systems/240075: ok i need help with graphing slope and y-intercept the equation is y=3-2x
1 solutions

Answer 176026 by rfer(2688) on 2009-11-17 20:00:04 (Show Source):

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y=3-2x
same as
y=-2x+3
y=mx+b
m=slope
b=y int
y=-2x+3

Rational-functions/240111: write an equation of a line that passes through the y-intercept -3 with slope 2
1 solutions

Answer 176025 by rfer(2688) on 2009-11-17 19:57:54 (Show Source):

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y=mx+b
y=2x-3

Graphs/240088: Graph the equation. I dentify the y intercept.
y=-2x-3

1 solutions

Answer 176024 by rfer(2688) on 2009-11-17 19:56:43 (Show Source):

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y=mx+b
m=slope
b=y int
y=-2x-3
b=-3

Functions/239603: 2X2-3=5
1 solutions

Answer 175826 by rfer(2688) on 2009-11-16 18:57:56 (Show Source):

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2x^2-3=5
2x^2=8
x^2=4
x=2

Graphs/239607: what is x and y-intercept for each problem
x+3y=9

and 2x+3y=6

and 4x-5y=10

and x +y =5
1 solutions

Answer 175825 by rfer(2688) on 2009-11-16 18:56:15 (Show Source):

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y int, x=0
x int, y=0
------------
x+3y=9
0+3y=9
y=3
(0,3)
-------------
x+3*0=9
x=9
(9,0)
you try the others.

Systems-of-equations/239616: 9 - 3a = -6 + 2a
1 solutions

Answer 175822 by rfer(2688) on 2009-11-16 18:51:00 (Show Source):

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9-3a=-6+2a
15=5a
a=3

Equations/239130: Please help me solve this equation: 3x + 1/3 = 7/5
(or three x plus one third equals seven fifths)
thanks.
1 solutions

Answer 175671 by rfer(2688) on 2009-11-15 19:07:56 (Show Source):

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3x+1/3=7/5
45/15x+5/15=21/15
45/15x=16/15
x=(16/15)/(45/15)
x=16/15*15/45
x=240/675
x=16/45

Surface-area/239160: what is the area of a square with sides 2 1\2inches long?
1 solutions

Answer 175669 by rfer(2688) on 2009-11-15 19:00:30 (Show Source):

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A=s^3
A=2.5^3
A=15.625 cu in

expressions/239144: 3(x+4)=5(x-2)
1 solutions

Answer 175667 by rfer(2688) on 2009-11-15 18:57:07 (Show Source):

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3(x+4)=5(x-2)
3x+12=5x-10
22=2x
x=11

Linear-equations/239175: 2/3x-7=-17
1 solutions

Answer 175664 by rfer(2688) on 2009-11-15 18:53:05 (Show Source):

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2/3x-7=-17
2/3x=-10
2x=-10*3
2x=-30
x=-15

Average/239183: A student averages 84 on five tests. If the student received grades of 84, 82, 81, and 79 on the first four exams, what grade did the student receive on the fifth exam?
1 solutions

Answer 175662 by rfer(2688) on 2009-11-15 18:50:28 (Show Source):

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(84+82+81+79+x)/5=84
326+x=84*5
326+x=420
x=420-326
x=94

Probability-and-statistics/239196: For every 210 high school students, there are 5880 people living in the community. If a community has 1325 high school students how many people live in the community?
1 solutions

Answer 175659 by rfer(2688) on 2009-11-15 18:46:37 (Show Source):

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1325/210=6.3
5880*6.3=37,044