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checkley77 answered: 12560 problems
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Angles/280382: Triangle with a 12' base,9' height,and 7' hypotenuse. Please Help And Show Work So i know.
1 solutions

Answer 203809 by checkley77(12569) About Me  on 2010-03-13 17:49:58 (Show Source):
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Is this a right triangle?
Are you trying to find the perimeter, the area or the angles?
Please clarify & resubmit.
--------------------------------------
I'll assume it's a right triangle.
12+9+7=28" ans. for the perimeter.


Proportions/280383: what is the solution for b/3=4/12
1 solutions

Answer 203807 by checkley77(12569) About Me  on 2010-03-13 17:45:15 (Show Source):
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b/3=4/12 cross multiply.
12b=12
b=12/12
b=1 ans.
Proof:
1/3=4/12
1/3=1/3


absolute-value/280388: Mark had a board 25 1/2 inches long which he cut into 10 pieces. How long would the board be if it had 17 pieces of the same thickness?
1 solutions

Answer 203803 by checkley77(12569) About Me  on 2010-03-13 17:42:37 (Show Source):
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25.5/10=2.55 IN. PER PIECE.
17*2.55=43.35 IN. BOARD ANS.


Travel_Word_Problems/280396: A boy swims downstream 0.9 miles in the same amount of time that he can swim 0.6 miles upstream. If the rate of the current is 1.5 mph, how fast can he swim in still water?
1 solutions

Answer 203801 by checkley77(12569) About Me  on 2010-03-13 17:39:38 (Show Source):
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D=RT
.9=(R+1.5)T SWIMMING DOWNSTREAM.
T=.9/(R+1.5)
.6=(R-1.5)T SWIMMING UPSTREAM.
T=.6/(R-1.5)
THE TIMES ARE THE SAME THUS SET THE TWO EQUATIONS EQUAL.
.9/(R+1.5)=.6/(R-1.5) CROSS MULTIPLY.
.9(R-1.5)=.6(R+1.5)
.9R-1.35=.6R=+.9
.9R-.6R=.9+1.35
.3R=2.25
R=2.25/.3
R=7.5 MPH IS THE SPEED OF THE SWIMMER IN STILL WATER.
PROOF:
.9/(7.5+1.5)=.6(7.5-1.5)
.9/9=.6/6
.1=.1


Probability-and-statistics/280399: A bag contains 8 red marbles, 4 green marbles and 3 yellow marbles. Find the following probabilities:
a. two marbles drawn from the bag with out replacement: the probability that both are yellow
b. two marbles are drawn from the bag with replacement. Find the probability that you draw a red and a yellow marble
1 solutions

Answer 203796 by checkley77(12569) About Me  on 2010-03-13 17:25:01 (Show Source):
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3/15*2/14=6/210=.02857 ans for 2 yellows without replacement.
2(8/15*3/15)=2(24/225)=48/225=.021333 ans. for a red then a yellow or a yellow then a red with replacement.


Graphs/280400: use the FOIL method to find the product:
(8x^3-2)(x^8-2)
1 solutions

Answer 203791 by checkley77(12569) About Me  on 2010-03-13 17:16:52 (Show Source):
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(8x^3-2)(x^8-2)
8x^11-16x^3-2x^8+4
8x^11-2x^8-16x^3+4 ans.


Volume/280401: LPG is stored in highly insulated spherical vessels in most oil refineries. If the inside diameter of one of these tanks is 11.4 ft find its volume. Report answer to the nearest one tenth of a gallon. Use pi = 3.14 and 1 cubic ft = 7.5 gallons.
1 solutions

Answer 203790 by checkley77(12569) About Me  on 2010-03-13 17:14:31 (Show Source):
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V=pir^2h
You've given me pi & r but no h.
Need an [H] value to solve.


Graphs/280402: If a basketball player has a vertical leap of about 25 inches. What is his hang-time? Use the hang-time function: V=48T^2
The hang time is ? secounds
1 solutions

Answer 203789 by checkley77(12569) About Me  on 2010-03-13 17:09:34 (Show Source):
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V=48T^2
25=48t^2
t^2=25/48
t^2=.521
t=sqrt.521
t=.722 seconds.


Money_Word_Problems/280404: A women invested 4 times as much at 5% as she did at 6%. The total amount of interest she earns in 1 year from both accounts is $520. How much did she invest at each rate?
1 solutions

Answer 203788 by checkley77(12569) About Me  on 2010-03-13 17:05:08 (Show Source):
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.05*4x+.06x=520
.20x+.06x=520
.26x=520
x=520/.26
x=520/.26
x=$2,000 invested @ 6%
4*2,000=$8,000 invested @ 5%
Proof:
.05*8,000+.06*2,000=520
400+120=520
520=520


Graphs/280408: Hi - I need to solve the following inequality if possible.
x/-7<-3
Thank You
1 solutions

Answer 203786 by checkley77(12569) About Me  on 2010-03-13 16:59:50 (Show Source):
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x/-7<-3 cross multiply
x>-3*-7 [note the sign change when multiplying by a negative value].
x>21 ans.
Proof:
Let x=21.1
21.1/-7<-3
-3.014<-3


Polynomials-and-rational-expressions/280409: Factor each polynomial.If the polynomial cannot be factored,write prime.
1.15r+20rs
2.7yz+3x
1 solutions

Answer 203784 by checkley77(12569) About Me  on 2010-03-13 16:57:09 (Show Source):
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IF you mean then:
1. 15r+20rs
5r(3+4s) ans.
2. 7yz+3x prime.
----------------------
IF you mean then:
1.15r+20rs
5(.23r+4s) ans.
2.7yz+3x
3(.9yz+x) ans.


Distributive-associative-commutative-properties/280411: Factor each polynomial.If the polynomial cannot be factored,Write prime.
4xy^2+18xy+14y
1 solutions

Answer 203780 by checkley77(12569) About Me  on 2010-03-13 16:52:18 (Show Source):
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4xy^2+18xy+14y
2y(2xy+9x+7)ans.


Proportions/280412: A technician has been given 100ml of a 10% acetic acid solution. The pharmacist asked the technician to dilute the solution of 500 ml with sterile water and to label the solution. What percent should appear on the label?
1 solutions

Answer 203777 by checkley77(12569) About Me  on 2010-03-13 16:49:20 (Show Source):
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IF the total mix is 500ml then:
.10*100=500x
10=500x
500x=10
x=10/500
x=.02 or thre mix is 2% acid.
-------------------------------------------
IF you're adding 500ml of water then:
.10*100=(100+500)x
10=600x
600x=10
x=10/600
x=.0167 or 1.67% acid.


Linear-systems/280414: I need help in solving the following equation. Thanks so much.
7[4x+2] + 6=4
1 solutions

Answer 203776 by checkley77(12569) About Me  on 2010-03-13 16:43:26 (Show Source):
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|4x+2| means the positive & the negative value of the term inside the bars.
7|4x+2|+6=4
28x+14+6=4
28x+20=4
28x=4-20
28x=-16
x=-16/28
x=-4/7 ans.
------------------
7*-(4x+2)+6=4
-28x-14+6=4
-28x=4+14-6
-28x=12
x=12/-28
x=-3/7 ans.


Percentage-and-ratio-word-problems/280346: 4 out of 40 boys failed in an examination. what percentage of boys failed and what percentage passed the examination?

1 solutions

Answer 203747 by checkley77(12569) About Me  on 2010-03-13 10:31:27 (Show Source):
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4/40=.1 or 10% failed.
1-.1=.9 or 90% passed.


Polynomials-and-rational-expressions/280352: The mass of Mars is about 6.421*10^20 metric tons. The mass of the sun is about 1.998*10^27 metric tons. About how many times the mass of Mars is the mass of the sun? Give your answer in scientific notation.
The mass of the sun is about ____ times the mass of mars.
(round to the nearest thousandth as needed. Use scientific notation. Use the multiplication symbol in the math palette as needed.
1 solutions

Answer 203746 by checkley77(12569) About Me  on 2010-03-13 10:29:46 (Show Source):
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1.998*10^27/6.421*10^20=3.11166485*10^6 ans.


Polynomials-and-rational-expressions/280353: (-10x+11)+(4x^2+1/2x-14)
simplify your answer. Use integers or fractions for any numbers in the expression.
1 solutions

Answer 203745 by checkley77(12569) About Me  on 2010-03-13 10:23:47 (Show Source):
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(-10x+11)+(4x^2+1/2x-14)
-10x+11+4x^2+x/2-14
4x^2-10x+x/2+11-14
4x^2-9.5x-3
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
x=(9.5+-sqrt[-9.5^2-4*4*-3])/2*4
x=(9.5+-sqrt[90.25+48])/8
x=(9.5+-sqrt[138.25])/8
x=(9.5+-11.758)/8
x=(9.5+11.758)/8
x=21.258/8
x=2.657 ans
x=(9.5-11.758)/8
x=-2.258/8
x=-.282 ans.


Polynomials-and-rational-expressions/280351: Simplify:
(3^2)^-4=

1 solutions

Answer 203744 by checkley77(12569) About Me  on 2010-03-13 10:10:48 (Show Source):
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(3^2)^-4=9^-4=1/9^4=1/6561 ans.


Linear-systems/280140: slove the follwing system of equation using subatitution 3x+6y=48 and-5x+6y=32
1 solutions

Answer 203678 by checkley77(12569) About Me  on 2010-03-12 19:30:49 (Show Source):
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3x+6y=48
6y=-3x+48 eq#1
-5x+6y=32
6y=5x+32 eq#2
set these 2 equations equal
-3x+48=5x+32
-3x-5x=32-48
-8x=-16
x=-16/-8
x=2 ans.
3*2+6y=48
6+6y=48
6y=48-6
6y=42
y=52/6
y=7 ans.
Proof:
-5*2+6*7=32
-10+42=32
32=32


Exponents-negative-and-fractional/280146: What is a^ negative 3 over 3b to the 4th power?
1 solutions

Answer 203676 by checkley77(12569) About Me  on 2010-03-12 19:24:08 (Show Source):
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a^-3/3b^4
1/a^3*3b^4
1/3a^3b^4 ans.


Miscellaneous_Word_Problems/280151: Find an equation of the line containing the given pair of points.
(1/6,- 1/3) and (5/6,5)

1 solutions

Answer 203675 by checkley77(12569) About Me  on 2010-03-12 19:21:41 (Show Source):
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Y=mX+b is the line equation.m=slope & b=Y intercept.
(1/6,- 1/3) and (5/6,5)
m=(y2-y1)/(x2-x1)
m=(5+1/3)/(5/6-1/6)
m=(16/3)/(4/6)
m=16/3*6/4
m=16*6/3*4
m=8 ans.
-1/3=8*1/6+b
-1/3=4/3+b
b=-1/3-4/3
b=-5/3 the Y intercept.
y=8x-5/3
+graph%28+300%2C+200%2C+-6%2C+5%2C+-10%2C+10%2C+8x+-5%2F3%29+ (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, 8x -5/3).


Equations/280221:
x2 -10x+24=0
1 solutions

Answer 203674 by checkley77(12569) About Me  on 2010-03-12 18:52:57 (Show Source):
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x^2-10x+24=0
(x-6)(x-4)=0
x-6=0
x=6 ans
x-4=0
x=4 ans.


Money_Word_Problems/280227: 0.3x-0.2y=4, 0.4x+0.5y= -55/17, What is the solution of the system. Use integers or fractions.
1 solutions

Answer 203672 by checkley77(12569) About Me  on 2010-03-12 18:50:37 (Show Source):
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0.3x-0.2y=4 multiply by 5
0.4x+0.5y=-55/17 multiply by 2 & add.
1.5x-y=20
.8x+y=110/17
--------------------
2.3x=20+110/17
2.3x=(20*17+110)/17
2.3x=(340+110)/17
2.3x=450/17 cross multiply.
2.3x*17=450
39.1x=450
x=450/39.1
x=11.51 ans
.3*11.51-.2y=4
3.453-.2y=4
-.2y=4-3.453
-.2y=.547
y=.547/-.2
y=-2.735 ans.
Proof:
.4*11.51+.5*-2.735=-55/17
4.604-1.367=-55/17
-3.236~-3.235



Miscellaneous_Word_Problems/279991: AN EXPEREINCED BANK AUDITOR CAN CHECK A BANK'S DEPOSIT TWICE AS FAST AS A NEW AUDITOR. WORKING TOGETHER IT TAKES THE AUDITORS 20 HOURS TO DO THE JOB. HOW LONG WOULD IT TAKE THE EXPERIENCED AUDITIOR WORKING ALONE?
1 solutions

Answer 203601 by checkley77(12569) About Me  on 2010-03-12 14:03:32 (Show Source):
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1/x+1/2x=1/20
(2x+x)/2x*x=1/20
3x/2x^2=1/20 cross multiply.
2x^2=3x*20
2x^2=60x cancel out one of the xs.
2x=60
x=30 hours for the experienced auditor.
Proof:
1/30+1/2*30=1/20
1/30+1/60=1/20
(60+30)/30*80)=1/20
90/1,800=1/20
1,800=90*20
1,800=1,800



Proportions/279993: There is a sales tax of $22 on an item that costs $275 before tax. A second item costs $87.50 before tax. What is the sales tax on the second item?

1 solutions

Answer 203599 by checkley77(12569) About Me  on 2010-03-12 13:58:27 (Show Source):
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22/275=.08 or 8% is the sales tax.
87.50*.08=$7.00 is the sales tax.


Proportions/279995: There are 480 dishes that need to be rinsed. John can rinse them in 80 minutes by himself. It will take his friend Bob 120 minutes to rinse these dishes. How long will it take them if they rinse these 480 dishes together?

1 solutions

Answer 203597 by checkley77(12569) About Me  on 2010-03-12 13:54:55 (Show Source):
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1/80+1/120=1/x
(120+80)/80*120=1/x
200/9,600=1/x cross multiply
200x=9,600
x=9,600/200
x=48 minutes working together.


Unit_Conversion_Word_Problems/280030: in 1991 the separation between college football goalpost uprights was reduced from 23 feet 4 inches to 18 feet 6 inches. to the nearest tenth of a percent, what was the reduction?
1 solutions

Answer 203595 by checkley77(12569) About Me  on 2010-03-12 13:49:34 (Show Source):
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(23*12+4)-(18*12+6)
(276+4)-(216+6)
280-222=58 inches less.
58/280=.21% reduction.


Linear-systems/280032: solve the linear system
-7x-8y=9
-4x+9y=-22

1 solutions

Answer 203591 by checkley77(12569) About Me  on 2010-03-12 13:37:29 (Show Source):
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-7x-8y=9 multiply by 9
-4x+9y=-22 multiply by 8 & add.
-63x-72y=81
-32x+72y=-176
--------------
-95x=-95
x=-95/-95
x=1 ans.
-7*1-8y=9
-7-8y=9
-8y=9+7
-8y=16
y=16/-8
y=-2 ans.
SOLUTION: (1,-2)
-7x-8y=9
-8y=7x+9
y=7x/-8+9/-8
y=-7x/8-9/8 (red line)
-4x+9y=-22
9y=4x-22
y=4x/9-22/9 (green line)
+graph%28+300%2C+200%2C+-6%2C+5%2C+-10%2C+10%2C+-7x%2F8+-9%2F8+%2C+4x%2F9+-22%2F9+%29+ (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, of TWO functions -7x/8 -9/8 and 4x/9 -22/9).


Permutations/280036: abelardo wants to create several different 7-charcater screen names. he wants to use arrangements of the first 3 letters of his first name (abe), followed by arrangements of 4 digints in 1984, the year of his birth. how many different screen names can he create in this way?
1 solutions

Answer 203586 by checkley77(12569) About Me  on 2010-03-12 13:26:49 (Show Source):
You can put this solution on YOUR website!
With repeats:
7^7=823,543 ans.
Without repeats:
7*6*5*4*3*2*1=5,040 ans.


Permutations/280037: a box contains 7 large red marbles 5 large yellow marbles 3 small red marbles and 5 small yellow marbles. if a marble is drawn at random what is the probability that is yellow, given that it is one of the large marbles
1 solutions

Answer 203584 by checkley77(12569) About Me  on 2010-03-12 13:20:58 (Show Source):
You can put this solution on YOUR website!
7+5+3+5=20 total marbles.
5/20=1/4=.25 or 25% chance of selecting a large yellow marble.


Equations/280071: 2a+6
------ = 6a+2
3
1 solutions

Answer 203581 by checkley77(12569) About Me  on 2010-03-12 13:12:50 (Show Source):
You can put this solution on YOUR website!
2a+6
------ = 6a+2
3
2a+6=3(6a+2)
2a+6=18a+6
2a-16a=6-6
-14a-0
a=0/-14
a=0 ans:
Proof:
(2*0+6)/3=6*0+2
6/3=2
2=2