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John is 5 years older than Mary. In 10 years, twice John's age decreased by Mary's age is 35, and John's age will be twice Mary's current age. Find their ages now.
John is years old ?, and Mary is ? years old.
1 solutions
Answer 190494 by richwmiller(9143)   on 2010-01-20 10:43:45 (Show Source):
You can put this solution on YOUR website!Again no idea what you mean by "two order system"
j=m+5 and
2(j+10)-(m+10)=35 and
j+10=2m
j=20
m=15
We can solve by just using the first and last equations.
j=m+5
j+10=2m
m+5+10=2m
m+15=2m
15=m
j=20
Just for fun lets check using the unused equation
2(j+10)-(m+10)=35
2(30)-25=35
60-25=35
35=35
ok
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Linear_Algebra/258778: 2x-4y=6
2x+y=1
my teacher said to solve this by using substitution but i keep getting the worng answer, help plz :)!
1 solutions
Answer 190489 by richwmiller(9143) on 2010-01-20 10:23:35 (Show Source):
You can put this solution on YOUR website!So what did you try?
What did you get?
2x-4y=6
2x+y=1
Substitution might be the harder way to solve this
Elimination would be
Subtract the two and get
-5y=5
y=-1
2x-1=1
2x=2
x=1
However we will do it by substitution.
Solve the second for y
y=1-2x
Substitute 1-2x for y in the first
2x-4(1-2x)=6
2x-4+8x=6
10x =10
x=1
y=1-2(1)
y=1-2
y=-1
Same answers
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Miscellaneous_Word_Problems/258760: The cost of a bus trip was $180. he people who signed up for the trip agreed to split the cost equally. However, six people did not show up , so that those who did go each had to pay $1.50 more. How many people actually went on the trip ?
1 solutions
Answer 190487 by richwmiller(9143) on 2010-01-20 10:17:05 (Show Source):
You can put this solution on YOUR website!p*c=180 and
(p-6)(c+1.5)=180
p=30 planned to go
c=6 original cost per person
p-6=24 went on trip
c+1.50=7.50 cost per person on trip
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Linear-systems/258775: Solve this problem by using a two order system.
One of two complementary angles is 8 degrees less than the other.
The numbers are__?__degrees and __?__degrees .
1 solutions
Answer 190485 by richwmiller(9143) on 2010-01-20 10:11:56 (Show Source):
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Travel_Word_Problems/258761: jacqui commutes 30 miles to her job each day. She finds that if she drives 10 miles/hour faster, it takes her 6 minutes less to get to work .find her new speed
1 solutions
Answer 190482 by richwmiller(9143) on 2010-01-20 10:06:58 (Show Source):
You can put this solution on YOUR website!rt=30
t=30/r
(r+10)(t-1/10)=30
(r+10)(30/r-1/10)=30
r=50
new speed 50+10=60
60(t-1/10)=30
t=3/5=36/60= 36 minutes
t-1/10=new time 30 minutes
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Unit_Conversion_Word_Problems/258568: HELP! I'm an old dog learning new stuff. I'm having trouble getting this to click in my old brain. I'm supposed to figure this out by using dimensional analysis.... Thanks so very much for your help!
If a block of ice measures 24 in. x 36 in. x 18 in.
(a) What is the volume of this block in cubic meters?
(b) What is the total surface area of the block in square centimeters?
1 solutions
Answer 190386 by richwmiller(9143) on 2010-01-19 19:46:01 (Show Source):
You can put this solution on YOUR website!You need your conversion factor to convert from cubic inches to cubic meters and square inches to square centimeters
1 inches = 0.0254 meters
http://vulcan.wr.usgs.gov/Miscellaneous/ConversionTables/conversion_table.html
you can convert before multiplying or after
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Linear-systems/258522: alright here goes lol. i tryed to solve it and came up with some strange answers.
1. 4x+2y+z=7
2x+2y-4z=-4
x+3y-2z=-8
My attempts: (sorry for the confusing factor x.x)
(4x+2y+z=7)4
2x+2y-4z=28
_____________
2x+2y=-4
16x+8y+28
___________
18x+10y=24
(4x+2y+z=7)2
x+3y-2z=-8
____________
8x+4x+2z=7
(9x+7y=-1)-2
18x+10y=24
____________
-18x-14y=2
18x+10y=24
___________
-4y = 26
___ ___
-4 -4
y=-6.5
18x+10(-6.5)=24
18x-65=24
__________
18x=89
x=4.94
4(4.94)+2(-6.5)+z=7
19.70-13+z=7
6.76+z=7
z=.24
thats it. im sorry its so confusing. im so very confused about this stuff so please help x.x
1 solutions
Answer 190336 by richwmiller(9143) on 2010-01-19 18:18:55 (Show Source):
You can put this solution on YOUR website!x = 3, y = -3, z = 1
Now for your attempt
(4x+2y+z=7)4
2x+2y-4z=28
_____________
2x+2y=-4
16x+8y+28
(4x+2y+z=7) *4
16x+8y+4z=28
What happened to the 4z and why only three terms?
From here on it is trouble.
Let's try again
4x+2y+z=7 (1)
2x+2y-4z=-4 (2)
x+3y-2z=-8 (3)
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Linear-equations/258517: I don't understand slopes and it seems difficult and i just don't understand it, please help!!
Lynn
1 solutions
Answer 190307 by richwmiller(9143) on 2010-01-19 17:33:46 (Show Source):
You can put this solution on YOUR website!Most new things seem difficult.
Give an example of the type of slope problem that stumps you.
There are too many aspects of slope to go into them all without an example of your troubles.
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Triangles/258450: If a triangle has two short sides that are each three and four inches in length, how long is the longest side?
1 solutions
Answer 190295 by richwmiller(9143) on 2010-01-19 17:02:30 (Show Source):
You can put this solution on YOUR website!If we knew that the angle between the two short sides is a right angle then the third side would be 5.
We do know that the third side must be less than 7.
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Polynomials-and-rational-expressions/258463: factoring by using trial factors 6z^2-7z+3.
1 solutions
Answer 190292 by richwmiller(9143) on 2010-01-19 16:55:39 (Show Source):
You can put this solution on YOUR website!
| Solved by pluggable solver: Factoring using the AC method (Factor by Grouping) |
In order to factor  , first multiply the leading coefficient 6 and the last term 3 to get 18. Now we need to ask ourselves: What two numbers multiply to 18 and add to -7? Lets find out by listing all of the possible factors of 18
Factors:
1,2,3,6,9,18,
-1,-2,-3,-6,-9,-18, List the negative factors as well. This will allow us to find all possible combinations
These factors pair up to multiply to 18.
1*18=18
2*9=18
3*6=18
(-1)*(-18)=18
(-2)*(-9)=18
(-3)*(-6)=18
note: remember two negative numbers multiplied together make a positive number
Now which of these pairs add to -7? Lets make a table of all of the pairs of factors we multiplied and see which two numbers add to -7
| First Number | | | Second Number | | | Sum | | 1 | | | 18 | || | 1+18=19 | | 2 | | | 9 | || | 2+9=11 | | 3 | | | 6 | || | 3+6=9 | | -1 | | | -18 | || | -1+(-18)=-19 | | -2 | | | -9 | || | -2+(-9)=-11 | | -3 | | | -6 | || | -3+(-6)=-9 |
None of these factors add to -7. So the quadratic cannot be factored. | |
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Travel_Word_Problems/258487: In June 2007, Carl Edwards won the Michigan 400 with a time of 2:42:5 for the 400 mi race. At one point, Edwards was 80 mi closer to the finish than the start. How far had Edwards traveled at that point?
1 solutions
Answer 190289 by richwmiller(9143) on 2010-01-19 16:48:13 (Show Source):
You can put this solution on YOUR website!At 200 miles he was equal distance from the start and finish.
At 220 he was 180 from the finish and 220 from the start- a difference of 40
At 240 he was 160 from the finish and 240 from the start a difference of 80 miles.
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Numbers_Word_Problems/258382: Sales tax in California is 6%. Create an equation for the total price (cost plus tax) of a purchase in CA in terms of its cost. How much would a person pay for a car whos cost is $32,000?
1 solutions
Answer 190259 by richwmiller(9143) on 2010-01-19 14:23:45 (Show Source):
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Numbers_Word_Problems/258441: There are 220 barrels of cement in one shed and 510 barrels in another shed. How many barrels must be transferred from the second to the first shed so that the first shed will contain two-thirds as much as the second shed?
1 solutions
Answer 190255 by richwmiller(9143) on 2010-01-19 14:10:15 (Show Source):
You can put this solution on YOUR website!(220+x)=2/3*(510-x)
x=72 to be moved
220+72=292
510-72=438
Note it does NOT say two thirds of the total barrels are in one place but the barrels in one place are two thirds of the barrels in the other
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Rectangles/258402: Children need to build a pen for their puppy using 24 square feet of fencing at .75 per foot. What is the dimensions and cost of the least expensive pen and the most expensive pen they can build?
1 solutions
Answer 190251 by richwmiller(9143) on 2010-01-19 14:04:58 (Show Source):
You can put this solution on YOUR website!If the children are going to build using 24 sqft there is no least nor most expensive. The quantity has been decided.
Your price .75 ft doesn't make sense. The fencing is square feet.
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Miscellaneous_Word_Problems/258411: You have 1 gallon of solution that is 20% salt and 80% water. You need 8 gallons of solution that is 2% salt and 98% water. How much water do you add to obtain this?
1 solutions
Answer 190234 by richwmiller(9143) on 2010-01-19 13:16:50 (Show Source):
You can put this solution on YOUR website!.8*1+x=8*.98
7.04 gallons
which works out in the equation but seems odd because 1 + 7.04 is more than 8
but if you add only 7 gallons it will tell that you are missing .04 gallons
Maybe the salt is absorbed into the solution?
.8*1+7=.98x
x=7.95918
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Linear-equations/258418: A printer has two presses. One has a setup cost of $210 and can print the pages of a certain book for $5.69. The other press has a setup cost of $350 and can print the pages of the same book for $5.31. Find the break point.
Could someone help me, please?
Thank you.
1 solutions
Answer 190233 by richwmiller(9143) on 2010-01-19 13:01:33 (Show Source):
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Money_Word_Problems/258413: alicia murphy has a choice of two sizes of stain and varnish.the 237 milliliter can sells for 3.96 while the 946 milliliter can sells for 7.96 which size is better buy? what must she consider other than price?
1 solutions
Answer 190230 by richwmiller(9143) on 2010-01-19 12:11:46 (Show Source):
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Travel_Word_Problems/258414: Hello, This comes from Algebra and Trigonometry 4th edition book.I can't figure the formula needed when I don't have the speed of something already.
A Leisure Time Cruise riverboat travels 46 km downstream in 2 hr. It travels 51 km upstream in 3 hr. Find the speed of the boat and the speed of the plane.
Thank you for your help!
1 solutions
Answer 190228 by richwmiller(9143) on 2010-01-19 12:03:45 (Show Source):
You can put this solution on YOUR website!speed * time =distance
also written as r*t=d
We know the time and the distance
Surely, if I told you that I went 60 miles in one hour you would say that I went 60 mph.
x*1=60
x=60
or if I told you that I went 120 miles in 2 hours you would know I went 60 mph.
x*2=120
x=60 again
But something is wrong with your problem.
It says"Find the speed of the boat and the speed of the plane. "
There is no plane mentioned.
r*2=46
r=? You can solve this!
and the other
r*3=51
r=51/3=?
so it should current not plane the current is 3
20+3=23
20-3=17
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Linear_Algebra/258389: Determine the shortest distance from (9,5) to 5x + 3y =15
1 solutions
Answer 190225 by richwmiller(9143) on 2010-01-19 11:36:33 (Show Source):
You can put this solution on YOUR website!I had to think a second about this one.
They are asking for the equation that for the line which passes through (9,5) and is perpendicular to 5x + 3y =15.
Then we need the intersection of the two lines and then the distance from the intersection to (9,5)
so find the slope of 5x + 3y =15
3y=15-5x
y=15/3-5x/3
m=-5/3
perpendicular slope would be 3/5
5=3/5(9)+b
25=27+5b
-2=5b
-2/5=b
y=3/5x-2/5
5x + 3y =15
5y=3x-2 and
3x-2=5y
3x-5y=2
5x+3y=15
9x-15y=6
25x+15y=75
34x=81
x = 81/34, y = 35/34
(9,5)
(81/34,35/34)
a^2+b^2=c^2
sqrt((9-81/34)^2 +(5-35/34)^2)=
7.7 units
Here are some other ways to do it. Some much shorter.
http://www.worsleyschool.net/science/files/linepoint/distance.html
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Miscellaneous_Word_Problems/258393: There are five more children in Ms. Brown's class than in mr. whites room. Ten children move from ms. browns room to mr. whites room. Now there are twice as many children in mr whites room as in ms browns room. How many children were in Ms. Browns room before the move?
1 solutions
Answer 190222 by richwmiller(9143) on 2010-01-19 11:16:52 (Show Source):
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Money_Word_Problems/258380: On the first day, Joe joined a secret club as its only member. Each day after that, one more member joined than on the previous day. What was the membership of the club after 40 days?
((( I did this: 40 multiplied by 2 ; because it says each day after one more member joined than on the previous. So then I got 80 and added joe and got 81???)))
1 solutions
Answer 190218 by richwmiller(9143) on 2010-01-19 10:53:27 (Show Source):
You can put this solution on YOUR website!day joined membership
0 0 0
1 1 1
2 2 3
3 3 6
4 4 10
5 5 15
6 6 21
7 7 28
8 8 36
9 9 45
10 10 55
11 11 66
12 12 78
13 13 91
The new total is the previous total plus the new day
#8 is 36 which is 1/2*8*9
#10 is 55 which is 1/2*10*11=55
#12 78 1/2 12*13=6*13
total = day*day+1*1/2
It also works with odd numbers
#11 11*12*1/2=66
so we have
t=d*(d+1)*1/2
t=40*41*1/2
t=20*41=820 after 40 days
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Miscellaneous_Word_Problems/258375: During the first two weeks of the semester, 5 students withdrew from Hailey's Algebra class, 8 students were added to the class, and 4 students were dropped as "no shows". By how many students did the original class size change?
1 solutions
Answer 190215 by richwmiller(9143) on 2010-01-19 10:31:24 (Show Source):
You can put this solution on YOUR website!We jus t have to note the changes
-5+8-4
=-9+8=
=-1
There is one less on the books for the class than at the beginning.
-5+8=+3
But since 4 never showed, there are three more in class than at the beginning
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