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Recent problems solved by 'JBarnum'

JBarnum answered: 2042 problems
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percentage/317270: Change these percents to fraction form.7.23%
1 solutions

Answer 227136 by JBarnum(2044) on 2010-06-24 16:27:23 (Show Source):

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7.23%=.0723
.0723= 723%2F10000

Linear-systems/317273: Solve the following system of equations.
3x+5y=-11
x-2y=11
(x,y)=?
1 solutions

Answer 227134 by JBarnum(2044) on 2010-06-24 16:24:02 (Show Source):

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3x%2B5y=-11

multiply this line by 3
3x-6y=33

subtract this from first line
11y=-44

(x,y)=(3,-4)

Age_Word_Problems/317263: ann is 7/10 of bob's age. in 4 years and will be 8/11 of bob's age. How old is Bob now?
1 solutions

Answer 227130 by JBarnum(2044) on 2010-06-24 16:06:27 (Show Source):

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A=%287%2F10%29B

%287%2F10%29B%2B4=%288%2F11%29B%2B%2832%2F11%29

%287%2F10%29B%2B%2844%2F11%29=%288%2F11%29B%2B%2832%2F11%29

%287%2F10%29B%2B%2812%2F11%29=%288%2F11%29B

LCD 10*11=110
%2812%2F11%29=%2880%2F110%29B-%2877%2F110%29B

multiply by 110
120=%283%29B

divide by 3
60=B

bob is 60 years old
ann is 42 years old

Radicals/317240: Subtract. The 3 is the index
3√54x - 3√2x^4
1 solutions

Answer 227128 by JBarnum(2044) on 2010-06-24 15:51:47 (Show Source):

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3sqrt%2854x%29-3sqrt%282x%5E4%29

im using the same 3 as index
3sqrt%283%5E3%2A2x%29-3sqrt%282x%2Ax%5E3%29

factor out the third powers
3%283sqrt%282x%29%29-x%283sqrt%282x%29%29

factor out the 3sqrt%282x%29

Equations/317245: Solve.
Selma is flying a kite. She lets out 80 feet of string. Her brother moves to a point where he is standing directly under the kite. He measures this distance to be 30 feet. How high is the kite?
1 solutions

Answer 227127 by JBarnum(2044) on 2010-06-24 15:42:22 (Show Source):

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triangle question
80=c
30=a
find b
a%5E2%2Bb%5E2=c%5E2

74.162 feet high

Trigonometry-basics/317237: 2/x+1=1/x-2
1 solutions

Answer 227125 by JBarnum(2044) on 2010-06-24 15:34:44 (Show Source):

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this isnt trig....
simple proportions
%282%2F%28x%2B1%29%29=%281%2F%28x-2%29%29

cross multiply
2x-4=x%2B1

Equations/317247: Solve.
A pool table is 95 inches long and 51 inches wide. What is the length of the diagonal of the pool table?
1 solutions

Answer 227122 by JBarnum(2044) on 2010-06-24 15:31:00 (Show Source):

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this is a triangle problem
a%5E2%2Bb%5E2=c%5E2

107.8239 inches

Miscellaneous_Word_Problems/317257: As a restaurant owner there are many decisions that you need to make on a daily basis, such as where to keep inventory levels. You wish to replenish your stock of dishes by purchasing 250 sets for your restaurant. You have two dish design from which to choose. One design costs $20 per set and the other $45 per set. If you only have $6,800 to spend, how many of each design should you order?
Hint:
Let x = the number of sets of $20 dishes and y = the number of sets of $45 dishes.
•Solve the equations for the different dish designs to be ordered with the desired technique: graphing, substitution, elimination, matrix.
•Explain how to check your solution for both equations.
PLEASE HELP.... I NEED TO ANASWER THIS TODAY AND IAM STUCK AND SWAMPED WITH OTHER WORK>>> THANK YOU!!!
1 solutions

Answer 227110 by JBarnum(2044) on 2010-06-24 15:16:34 (Show Source):

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x+y=250
20x+45y=6800

x=250-y
20x%2B45y=6800
20%28250-y%29%2B45y=6800
%285000-20y%29%2B45y=6800
5000%2B25y=6800
25y=1800
y=72

x=250-y
x=250-72
x=178

checking
20x%2B45y=6800
20%28178%29%2B45%2872%29=6800
3560%2B3240=6800
6800=6800
correct
Checking
x%2By=250
178%2B72=250
250=250
correct

Equations/317249: Solve.
Dana drove her car from her house to her school. She went 7 miles due west and 3 miles due south. How far is Dana's house from the school?
1 solutions

Answer 227102 by JBarnum(2044) on 2010-06-24 14:50:53 (Show Source):

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this is a triangle problem
3%5E2%2B7%5E2=c%5E2

7.61 miles

Triangles/317253: An angle exceeds 4 times it’s supplement. Find the new angle formed if supplement is 30 degree.
1 solutions

Answer 227100 by JBarnum(2044) on 2010-06-24 14:45:09 (Show Source):

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supplement has 2 angles that add up to 180
4*30=120
the angle exceeds 120
180-30=150
150 has to be the angle if its supplement is 30

Equations/317227: John bought a .60 donut and .35 cup of coffee. How much did John leave for a tip and taxes if he spent 1.25? Assign a variable and write an equation for the situation then solve.
1 solutions

Answer 227099 by JBarnum(2044) on 2010-06-24 14:40:50 (Show Source):

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.60+.35=.95
theres a 7% tax here in florida, unless u specify differently im using floridas tax. with rounding up theres 7 cents tax
.95+.07=1.02
1.25-1.02=.23 tip
.23/1.02=22.5% tip

Inequalities/317231: 5 + (-8)>4 (-2) + 1
1 solutions

Answer 227086 by JBarnum(2044) on 2010-06-24 13:34:42 (Show Source):

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just calculate it
-3>-7

Angles/317229: Find the measure of the complement of an angle that measures 64°.
1 solutions

Answer 227085 by JBarnum(2044) on 2010-06-24 13:33:16 (Show Source):

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complement is for 2 angles that add to 90
so 90-64=26
26 degrees

real-numbers/317036: how do you prove that 0.37 is a rational number?

1 solutions

Answer 226971 by JBarnum(2044) on 2010-06-23 20:44:03 (Show Source):

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define it and show that irrational numbers dont stop example %28pi%29

=3.1415926535.....

Inequalities/317032: Add and simplify if possible.
6x / x^2 - 4 + x / x - 2
1 solutions

Answer 226970 by JBarnum(2044) on 2010-06-23 20:41:44 (Show Source):

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well acording to above doing order of opperations
%286x%2Fx%5E2%29-4%2B%28x%2Fx%29-2

Linear_Equations_And_Systems_Word_Problems/317016: A man divided $9,000 among his wife, son, and daughter. The wife received twice as much as the daughter, and the son received $1,000 more than the daughter. How much did each receive?
If x is the amount the wife received, then which of the following expressions represents the amount received by the son?
1 solutions

Answer 226967 by JBarnum(2044) on 2010-06-23 20:27:05 (Show Source):

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i like using the first letter of the names as my variables
w=wife
s=son
d=daughter
w+s+d=9000
w=2d
s=1000+d
solve for d
%282d%29%2B%281000%2Bd%29%2Bd=9000

w=2d
w=4000

s=1000%2Bd
s=3000

as far as the second part i cant see the selection of equations that u can

Linear_Equations_And_Systems_Word_Problems/317015: Solve this problem on paper using all four steps.
A girl scout troop sold cookies. If the girls sold 5 more boxes the second week than they did the first, and if they doubled the sales of the second week for the third week to sell a total of 431 boxes of cookies, how many did they sell each week?

1 solutions

Answer 226966 by JBarnum(2044) on 2010-06-23 20:19:53 (Show Source):

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x=week 1 amount
y=week 2 amount
z=week 3 amount

y=5+x
2y=z
x+y+z=431

solve for x
x%2B%285%2Bx%29%2B2%285%2Bx%29=431
x%2B%285%2Bx%29%2B%2810%2B2x%29=431
15%2B4x=431
4x=416
x=104

y=5%2B%28104%29
y=109

2%28109%29=z
218=z

Proportions/317013: The school cafeteria has found that they go through 9 sandwiches for every 7 tickets they sell to the students. Today they have 546 tickets for sale. How many sandwiches do they need to make?

1 solutions

Answer 226964 by JBarnum(2044) on 2010-06-23 20:12:08 (Show Source):

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proportions
9%2F7=x%2F546

cross multiply
9%28546%29=7x

multiply

divide by 7
702=x

702 sandwiches

decimal-numbers/317025: what is the fraction form of 1.38?
1 solutions

Answer 226962 by JBarnum(2044) on 2010-06-23 20:08:50 (Show Source):

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138%2F100

______ 1.38*100=138 ______ 138/100=1.38
69%2F50

this is its reduced form

Linear_Equations_And_Systems_Word_Problems/317017: Solve this problem on paper using all four steps.
Ted weighs twice as much as Julie. Mike weighs three times as much as Julie. Together, Ted, Mike, and Julie weigh 210 lbs. What is the weight of each person?
Julie weighs pounds, Ted weighs pounds, and Mike weighs pounds.

1 solutions

Answer 226961 by JBarnum(2044) on 2010-06-23 20:06:01 (Show Source):

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T=2J

"Ted weighs twice as much as Julie"
M=3J

"Mike weighs three times as much as Julie"
T%2BM%2BJ=210

"Together, Ted, Mike, and Julie weigh 210 lbs"

%282J%29%2B%283J%29%2BJ=210 add like terms
6J=210 divide by 6
highlight%28J=35%29

T=2J
T=2%2835%29
highlight%28T=70%29

M=3J
M=3%2835%29
highlight%28M=105%29

Checking
T%2BM%2BJ=210
70%2B105%2B35=210
210=210

Polynomials-and-rational-expressions/316975: Factor:
25v^2-w^2
1 solutions

Answer 226905 by JBarnum(2044) on 2010-06-23 16:53:23 (Show Source):

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its a perfect square %285v-w%29%285v%2Bw%29

Linear-equations/316946: What are the x and y intercepts and how do you find them? What are the x and y intercepts for the linear equation 2x + 3y = 15?
1 solutions

Answer 226903 by JBarnum(2044) on 2010-06-23 16:52:15 (Show Source):

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put line in slope intercept form y=mx+b
b=y-intercept
set y=0 to find x-intercept
3y=-2x+15
y=(-2/3)x+5
5=y-intercept
0=(-2/3)x+5
-5=(-2/3)x
-15=-2x
15/2=x-intercept

Polynomials-and-rational-expressions/316972: solving polynomial equations by factoring
5r^3 +15r^2-20r
the solutions is ________________
1 solutions

Answer 226901 by JBarnum(2044) on 2010-06-23 16:39:46 (Show Source):

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5r%5E3%2B15r%5E2-20r

factor out 5r
5r%28r%5E2%2B3r-4%29

two numbers that multiply to get -4 and add to get +3 are -1&4
5r%28r-1%29%28r%2B4%29

completely factored

Radicals/316971: simplify: sqrt (121/9)
a) sqrt (11) / sqrt (3)
b) 3 sqrt (11)
c) 11/3
d) sqrt (11) / (3)
1 solutions

Answer 226900 by JBarnum(2044) on 2010-06-23 16:36:28 (Show Source):

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sqrt%28121%2F9%29

Evaluation_Word_Problems/316970: a certain type of gutter comes in 6 foot and 10 foot sections. How many different lengths can be formed usin g3 sections of gutter?

1 solutions

Answer 226899 by JBarnum(2044) on 2010-06-23 16:34:47 (Show Source):

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well if u write out the 4 possibilities
6+6+6=18
6+6+10=22
6+10+10=26
10+10+10=30
so there are only 4 different lengths

Rectangles/316950: The perimeter of a rectangle is 140m. The length is 1m more than twice the width. Find the dimensions.
1 solutions

Answer 226897 by JBarnum(2044) on 2010-06-23 16:30:09 (Show Source):

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p=2l+2w
p=140
l=1+2w

140=2(1+2w)+2w
140=2+4w+2w
140=2+6w
138=6w
23=w
l=1+2(23)
l=1+46
l=47

Radicals/316968: simplify the following radical expression: sqrt (3) * sqrt (3)
a) none or 0
b) sqrt (3)
c) 3
d) 1

1 solutions

Answer 226895 by JBarnum(2044) on 2010-06-23 16:25:06 (Show Source):

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sqrt%283%29%2Asqrt%283%29

Inequalities/316954: Solve the inequality for y.
16 less than or equal to y + 5
1 solutions

Answer 226893 by JBarnum(2044) on 2010-06-23 16:23:18 (Show Source):

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16%3C=y%2B5

subtract 5
highlight%2811%3C=y%29

Linear-systems/316964: A 96 inch board is cut into two pieces, one piece is 8 inches longer than the other. how long should each piece be?
1 solutions

Answer 226892 by JBarnum(2044) on 2010-06-23 16:21:30 (Show Source):

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x%2By=96

Numbers_Word_Problems/316965: If twice a number is added to 3 and is divided by the muber plus 1 the result is three halve. What is the number?
1 solutions

Answer 226891 by JBarnum(2044) on 2010-06-23 16:17:31 (Show Source):

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personally i think thats a poorly written word problem if in book or by a teacher...Id simply state: "If twice a number added to 3 and divided by the number plus 1 is three halves, what is the number?"
%282n%2B3%29%2F%28n%2B1%29=%283%2F2%29

id treat this the same way one would solve a proportion, that being cross multiplying
2%282n%2B3%29=3%28n%2B1%29

distribute
%284n%2B6%29=%283n%2B3%29

subtract 3n
n%2B6=3

subtract 6
highlight%28n=-3%29

Check

%282%28-3%29%2B3%29%2F%28%28-3%29%2B1%29=%283%2F2%29

%28%28-6%29%2B3%29%2F%28-2%29=%283%2F2%29

Correct

Average/316966: the average mark of 4 tests is 72 if the numbers are 60 and 80 find the third number
1 solutions

Answer 226890 by JBarnum(2044) on 2010-06-23 16:07:58 (Show Source):

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dont u mean 3 tests since theres clearly no indication to find the 4th one and with a 2nd variable it would make for an incredible guess and check question with lots of possibilities. so im going to assume u meant 3 tests
%2860%2B80%2Bx%29%2F3=72

just to show u what the problem would be with 2 unknowns:
%2860%2B80%2Bx%2By%29%2F4=72
%28140%2Bx%2By%29=288
%28x%2By%29=148
as u can se there are many possibilities for what x or y could be, which would make a question like this unanswerable.

good luck

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Recent problems solved by 'JBarnum'