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unlockmath answered: 1598 problems
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Numbers_Word_Problems/353869: One number is 4 more than three times a smaller number. If twice the larger number is decreased by three times the smaller number, the result is 32.
1 solutions
Answer 252958 by unlockmath(1599)   on 2010-10-09 10:49:30 (Show Source):
You can put this solution on YOUR website!Hello,
Let's set up x being the smaller number and y will be the larger one. We can set up 2 equation as:
y=3x+4
2y-3x=32
rewritten as:
y-3x=4
2y-3x=32
Multiply the first equation by -2 to get:
-2y+6x=-8
Add this to the second equation:
3x=24
Divide by 3 to get:
x=8
Therefore y=28
Make sense?
RJ
www.math-unlock.com
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Average/353730: While on a safari in Africa I saw a small herd of zebras and cranes wandering over the grassland. I counted 18 heads in all and counted 60 legs. How many zebras were there and how many cranes.
1 solutions
Answer 252867 by unlockmath(1599) on 2010-10-08 22:05:15 (Show Source):
You can put this solution on YOUR website!Hello,
We can set up 2 equations. Let c represent cranes and z will be zebras.
c+z=18
2c+4z=60
Multiply the first by -2 to get:
-2c-2z=-36
Add this to the second equation to get:
2z=24
Divide by 2 to get:
z=12
There we go. 12 zebras and 6 cranes.
Make sense?
RJ
www.math-unlock.com
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Expressions-with-variables/353251: Solve the formulas below for the indicated variable. Show your work.
E/R+r =1, for R
I really don't even understand what they mean here, I'd really appreciate some help! Thank you!
1 solutions
Answer 252414 by unlockmath(1599) on 2010-10-07 15:27:35 (Show Source):
You can put this solution on YOUR website!Hello,
Basically all it's calling for is to get R by itself on one side of the =.
E/R+r =1, for R
First we multiply by R to get it out of the denominator.
E+rR =1R
Subtract E and R from both sides to get: (Note 1R is the same as R)
rR-R=-E
rewrite as:
R(r-1)=-E
Now Divide by r-1 to get:
R=-E/(r-1)
Make sense?
RJ
www.math-unlock.com
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Volume/352679: twice a number, added to 3, is equal to the negative of the number. What is the number?
1 solutions
Answer 252072 by unlockmath(1599) on 2010-10-06 13:34:30 (Show Source):
You can put this solution on YOUR website!Hello,,
Let x be the number so we can set up the following equation:
2x+3=-x
Subtract 3 and add x to both sides to get:
3x=-3
Divide by 3 to get:
x=-1
Got it?
RJ
www.math-unlock.com
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Rectangles/352672: Find the perimeter of a square that has diagonals 6 feet long.
1 solutions
Answer 252070 by unlockmath(1599) on 2010-10-06 13:32:10 (Show Source):
You can put this solution on YOUR website!Hello,
With this we can use the Pythagorus Formula to solve the sides.
Let x be the sides of the square so our equation will be:
x^2+x^2=6^2
Rewritten as:
2x^2=36
Divide by 2 to get:
x^2=18
Sq rt both sides to get:
x=sq rt 18
There we go. A side is sq rt 18 ft or approx 4.24 feet times 4 gives us a perimeter of 16.96 feet.
Make sense?
RJ
www.math-unlock.com
|
Miscellaneous_Word_Problems/352009: Two more than four times a numbers eight less than six times the number. Find the number.
1 solutions
Answer 251475 by unlockmath(1599) on 2010-10-04 22:45:26 (Show Source):
You can put this solution on YOUR website!Hello,
I wonder if you copied the problem exactly?
Anyway, I'm assuming there is an "is" after the word "number".
If so the equation will look like this if we have x represent the number:
2+4x=6x-8
Subtract 4x and add 8 to both sides to get:
10=2x
Divide by 2:
x=5
Make sense?
(Note: The word "is" in word problems usually stand for "=" equal signs.)
RJ
www.math-unlock.com
|
Travel_Word_Problems/351741: Two ants race across a table 72 cm long. One travels at 4.23 cm/s and the other at
3.99999 cm/s. When the first one crosses the finish line,
how far behind is the second one? Answer in units of cm.
1 solutions
Answer 251343 by unlockmath(1599) on 2010-10-04 15:35:10 (Show Source):
You can put this solution on YOUR website!Hello,
Let's first find how long it takes for the first one to get to the finish lime.
We divide 72 by 4.23 to get:
17.02 seconds (rounded off)
Now multiply this by 3.99999 to get:
68.08 cm the second ant has traveled.
So we subtract this from 72 cm to get:
3.92 cm behind the first ant. Close race.
Make sense?
RJ
www.math-unlock.com
|
Linear-equations/351735: check the solution algebraically....
2x+y=13
5x-2y=1
1 solutions
Answer 251340 by unlockmath(1599) on 2010-10-04 15:21:28 (Show Source):
You can put this solution on YOUR website!Hello,
Multiply the first equation by 2:
2x+y=13
5x-2y=1
Which will give us:
4x+2y=26
Now add this to the second equation to get:
9x=27
Divide by 9:
x=3
Now we can plug this to get y:
y=7
Make sense?
RJ
www.math-unlock.com
|
Rectangles/351137: This is a mathematics problem which one of my cousin asked me yesterday. He is in grade 4. However, I cannot help him because I am not good in maths.
The width of a rectangle is 20 cm more than half the length.
Its area is 4800 sq.cm.
Find its width.
1 solutions
Answer 250977 by unlockmath(1599) on 2010-10-03 10:54:14 (Show Source):
You can put this solution on YOUR website!Hello,
Well, this seems a bit advanced for a 4th grader.
First we'll let x show one side and 1/2x+20 for the other side.
Now we can set up an equation:
x(1/2x+20)=4800
Expand this out to:
1/2x^2+20x=4800
Subtract 4800 from both sides to get:
1/2x^2+20x-4800=0
Multiply by 2 to get rid of the fraction:
x^2+40x-9600=0
This can be factored as:
(x-80)(x+120)=0
solve for x to get:
x=80
x=-120
80 is the sensible answer, so the sides are
80 cm and 60 cm
This can be checked by multiplying these to get 4800 sq cm
Got it?
RJ
www.math-unlock.com
|
test/351139: identify terms,like terms, coefficents, and constant terms
x+5-3x-1
1 solutions
Answer 250974 by unlockmath(1599) on 2010-10-03 10:39:06 (Show Source):
You can put this solution on YOUR website!Hello,
Good problem so you can understand the words of Algebra.
Terms are each one for example:
x+5-3x-1
x is a term and 5 and -3x and -1
Like terms are:
x and -3x
5 and -1
Coefficients are:
-3 and actually there is a 1 in front of the x but these are usually not shown.
Constant terms are:
5 and -1
(Hint: Understanding the words is the first step to pulling off good grades in any subject)
Got it?
RJ
www.math-unlock.com
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Numbers_Word_Problems/350664: At the city museum, child admission is $5.40 and adult admission is $8.90 . On Monday, twice as many adult tickets as child tickets were sold, for a total sales of $626.40 . How many child tickets were sold that day?
1 solutions
Answer 250639 by unlockmath(1599) on 2010-10-01 14:27:52 (Show Source):
You can put this solution on YOUR website!Hello,
Let's have x be the number of children tickets and 2x will be the adults. Now we can set up the following equation:
5.4x+8.9(2x)=626.4
Expand this out:
5.4x+17.8x=626.4
Combine like terms:
23.2x=626.4
Divide both sides by 23.2 to get:
x=27
There we go,
27 children tickets were sold.
Make sense?
RJ
www.math-unlock.com
|
Quadratic_Equations/350627: two facing pages product of page # 210 what are page numbers?
1 solutions
Answer 250636 by unlockmath(1599) on 2010-10-01 14:19:26 (Show Source):
You can put this solution on YOUR website!Hello,
Let x be one page and (x+1) be the next so we can set up the following equation:
x(x+1)=210
Expand this:
x^2+x=210
Subtract 210 from both sides to get:
x^2+x-210=0
This can be factored as:
(x+15)(x-14)=0
Solve for x:
x=-15
x=14
14 is the sensible answer. So the pages are:
14 & 15
Make sense?
RJ
www.math-unlock.com
|
Equations/349981: The difference of two numbers is 42. The larger number is three less than six times the smaller number. Find the numbers.
1 solutions
Answer 250140 by unlockmath(1599) on 2010-09-29 22:47:40 (Show Source):
You can put this solution on YOUR website!Hello,
For this one we can set up 2 equations as:
x-y=42
x=6y-3
Multiply the first equation by -1 to get:
-x+y=-42
Add this to the second equation to get:
-5y=-45
Divide by -5 to get:
y=9
x=51
Make sense?
RJ
www.math-unlock.com
|
Numeric_Fractions/349693: How do you convert a decimals into a fractions???
1 solutions
Answer 249943 by unlockmath(1599) on 2010-09-29 13:10:15 (Show Source):
You can put this solution on YOUR website!Hello,
Let's take an example. It might show you easier.
Example:
.23
How do you say this?
23 hundredths
Right? The "hundredths" gives you a clue how to write the fraction;
23/100
Try another one.
.7819
This is said as, 7,819 ten thousandths so the fraction is:
7819/10,000
Got it?
RJ
www.math-unlock.com
|
Equations/349495: Identify the property or operation that is illustrated: 2*7=7*2
(a) Commutative property of addition
(b) Associative property of addition
(c) Distributive property of multiplication over addition
(d) Commutative property of multiplication
1 solutions
Answer 249785 by unlockmath(1599) on 2010-09-28 22:10:36 (Show Source):
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Linear_Equations_And_Systems_Word_Problems/349191: A man bought 7 pounds of coffee and 10 pounds of butter for a total of $58.50 .
A day later, the prices had not changed and he bought 7 pounds of coffee and 5 pounds of butter for $39.75 .
Find the price per pound of the butter.
1 solutions
Answer 249631 by unlockmath(1599) on 2010-09-28 13:31:36 (Show Source):
You can put this solution on YOUR website!Hello,
Let's have x be the cost for coffee and y be the cost for butter. We can set up 2 equations from this:
7x+10y=58.5
7x+5y=39.75
Multiply the second equation by -2 to get:
-14x-10y= -79.5
Now add this to the first equation to get:
-7x=-21
Now divide both sides by -7 to get:
x=3
y=3.75
There we go--butter is $3.75 per pound.
Make sense?
RJ
www.math-unlock.com
|
Miscellaneous_Word_Problems/348659: A construction has 152 bricks that are 1 foot long each and wants to enclose a rectangle. If the length is 50 feet more than the width, find the width and length of the rectangle.
1 solutions
Answer 249257 by unlockmath(1599) on 2010-09-27 11:53:43 (Show Source):
You can put this solution on YOUR website!Hello,
Let's have x represent the width. Now we can set up an equation as:
2x+2(x+50)=152
Following me? Now combine like terms and subtract 100 from both sides to get:
4x=52
Divide each side by 4 to get:
x=13
So the width is 13 bricks and length is 63 bricks or feet.
Make sense?
RJ
www.math-unlock.com
|
Equations/347766: solve for x:
x+4/5+x-1/4=37/10
1 solutions
Answer 248682 by unlockmath(1599) on 2010-09-24 23:25:44 (Show Source):
You can put this solution on YOUR website!Hello,
Let's get rid of the fractions in this x+4/5+x-1/4=37/10 by multiplying it by 20:
20x+16+20x-5=74
Now combine like terms and subtract both sides by 11 to get:
40x=63
Divde both sides by 40:
x=63/40 or 1 23/40
Got it?
RJ
www.math-unlock.com
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