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Linear-systems/253410: Pam is playing with red and black marbles. The number of red marbles she has is three more than twice the number of black marbles she has. She has 42 marbles in all how many red marbles does Pam have?
I got 29 red marbles but i am not sure if the equation i used to solve it was correct.
2x+3=42
1 solutions
Answer 185697 by richwmiller(9143)   on 2010-01-03 23:13:08 (Show Source):
You can put this solution on YOUR website!r+b=42
r=3+2b
Contrary to what my esteemed colleague has said, No, your equation was not correct.
You set up 3+2x=42
Your 3+2x should be the number of red marbles.
42 is the total number of marbles red + black
3+2b+b=42
3+3b=42
3b=39
b=13 black marbles
42-13=29 red marbles
I don't see how you calculated the correct 29 red marbles.
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expressions/253422: use this expression and evaluate 4x+4
1 solutions
Answer 185692 by richwmiller(9143) on 2010-01-03 22:55:26 (Show Source):
You can put this solution on YOUR website!4x+4 is a very nice expression. I highly recommend it.
It is known to be honest and hard working. I have been able to depend on 4x+4 for many years now.
I heartily endorse 4x+4. Please consider adopting or hiring 4x+4. You won't regret it.
4x+4=4(x+1)
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Geometry_proofs/253336: given: congruent triangle abc and congruetnt triangle edc, c is the midpoint of line bd and line ae. Prove: ab is equal and similar to line de
1 solutions
Answer 185691 by richwmiller(9143) on 2010-01-03 22:51:34 (Show Source):
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Probability-and-statistics/253419: two fair number cubes numbered 1 through 6 are tossed, what two sums are least likely to occur? explain your answer
1 solutions
Answer 185688 by richwmiller(9143) on 2010-01-03 22:46:41 (Show Source):
You can put this solution on YOUR website!2 and 12
2-1,1 each has to be one
3-1,2 2,1 either can be 1 or 2
4 2,2 3,1 1,3
5 1,4 4,1 2,3 3,2
6 1,5 5,1 2,3 3,2 4,1 1,4
7
8
9
10
11 6,5 5,6
12 6,6 both must be 6
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Geometry_proofs/253416: Can some one help me with a 2 column proof with the columns being statments and reasons
Given: < BAD APPROXIMATELY BUT NOT ACTUALLY EQUAL TO
Line AD is perpendicular to line BC
Prove: Triangle ABC is isosceles
Note: The picture looks like two right triangles that are put together to make one big one.
1 solutions
Answer 185682 by richwmiller(9143) on 2010-01-03 22:22:23 (Show Source):
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Linear_Algebra/253409: "Plumber Greg came to fix the Brown’s sink. He worked for four hours. The bill for the Browns was $34.59. Then he fixed the Minnick’s septic tank which took him 7 hours. The total bill was $55.23."
What is the independent and dependent variable?
1 solutions
Answer 185676 by richwmiller(9143) on 2010-01-03 22:08:01 (Show Source):
You can put this solution on YOUR website!(Independent variable) causes a change in (Dependent Variable) and it isn't possible that
(Dependent Variable) could cause a change in (Independent Variable).
Ask yourself -
Could the bill (total charges) affect the number of hours or the hourly charge ?
or
Could the number of hours or hourly charge change the total charges (bill) ?
Use in mathematics
In traditional calculus, a function is defined as a relation between two terms called variables because their values vary. Call the terms, for example, x and y. If every value of x is associated with exactly one value of y, then y is said to be a function of x. It is customary to use x for what is called the "independent variable," and y for what is called the "dependent variable" because its value depends on the value of x.[1] Therefore, y = x2 means that y, the dependent variable, is the square of x, the independent variable.[1][2]
The most common way to denote a "function" is to replace y, the dependent variable, by f(x), where f is the first letter of the word "function." Thus, y = f(x) = x2 means that y, a dependent variable, a function of x, is the square of x. Also, in this form, the expression is called an "explicit" function of x, contrasted with x2 − y = 0, which is called an "implicit" function.[1]
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Rectangles/253338: Assume 200 students attend a dance. It costs $350 plus $1.25 for each ticket sold. What is the cost per ticket you need to cover your expenses?
1 solutions
Answer 185630 by richwmiller(9143) on 2010-01-03 19:11:14 (Show Source):
You can put this solution on YOUR website!This was part of more complicated problem in the last weeks.
350=1.25*x
He needs to charge at least $1.75 if only 200 attend the dance. to the 350
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Exponents-negative-and-fractional/247669: what is the solution of this problm.
1000*[1-(1+0.05)^-5/0.05
1 solutions
Answer 185604 by richwmiller(9143) on 2010-01-03 18:04:43 (Show Source):
You can put this solution on YOUR website!Spell correctly and use proper grammar and punctuation.
What was the question?
There seems to be an opening bracket in the middle of the problem but no closing bracket. Should I guess where the closing bracket goes? If so, I'll guess at the answer too.
It also unclear as to what is over the .05. Perhaps that is where the closing bracket belongs. If the bracket goes before/0.05 then the answer is 4329.48
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Angles/253301: if the measure of an angle exceeds the measure of its compliment by 20, what is the measure of the angle?
1 solutions
Answer 185600 by richwmiller(9143) on 2010-01-03 17:53:00 (Show Source):
You can put this solution on YOUR website!They are just trying to confuse you with this fancy talk of exceed which just means it is more than.
The key question is what is the complement?
Complementary angles add up to 90.
so we have
x=y+20
x-y=20
x+y=90
add the last two equations
2x=110
x=55
y=90-55=35
check
35+55=90
55-35=20
ok
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Geometry_Word_Problems/253306: how do you solve 21=1/2(8x-18)-x? I know x=10 but I don't know the proper way of getting the answer.
1 solutions
Answer 185594 by richwmiller(9143) on 2010-01-03 17:37:31 (Show Source):
You can put this solution on YOUR website!take it step by step
The first thing to do is get rid of the parentheses. How?
multiply out 1/2(8x-18)
1/2 *8x=4x
1/2(-18)=-9
don't forget the minus sign
so now we have 21=4x-9-x
combine terms
21=3x-9
add 9 to both sides
30=3x
10=x
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Age_Word_Problems/253305: mary is twice mark's age; if the difference in their ages are 24. how old is mark
1 solutions
Answer 185593 by richwmiller(9143) on 2010-01-03 17:30:30 (Show Source):
You can put this solution on YOUR website!For everything we know, we write an equation.
mary=y
mark=k
y=2k
y-k=24
We can do this several ways.
Since we already have one equation y=2k let's substitute 2k for y in the other
2k-k=24
k=24
y=2k
y=48
mary is 48 and mark is 24.
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Linear-equations/253289: how do i plot the rise over run in a grid???????????????????????????????????????????????????????
1 solutions
Answer 185578 by richwmiller(9143) on 2010-01-03 16:56:40 (Show Source):
You can put this solution on YOUR website!In other words, you want to plot some points on a graph.
The rise is the difference in the y's and the run is the difference in the x's
The rise over the run is another way of describing the slope or gradient or slant of the line.
Do you have some points along with the assignment?
Or maybe an equation?
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Linear-systems/253285: The tens-digit of a three digit number is 3 less than 5 times the units digit. Three times the sum of the digits is 2 more than 4 times the hundreds digit. If the digits are reversed, the new number is 594 less than the original number. Find the original number. (find a system of 3 equations then use the system to find the original number).
1 solutions
Answer 185572 by richwmiller(9143) on 2010-01-03 16:32:43 (Show Source):
You can put this solution on YOUR website!Why do we need three equations? We need three equations because we will have three unknowns. We need one equation for each unknown.
Let the digits be h, t and u
Let the number be 100h+10t+u
t=5u-3
3*(h+t+u)=2+4h
100u+10t+h+594=100h+10t+u
721
h=7
t=2
u=1
check
2=5*1-3
2=5-3=2 ok
3*(7+2+1)=2+4*7
3*10=2+28
30=30 ok
127+594=721
721=721 ok
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Expressions-with-variables/253286: Erin's age is 3 times Warren's. In 4 years she will be twice as old as he will be. How old is each now?
so far I have {E+4 = 2(w x 3 + 4)}
1 solutions
Answer 185570 by richwmiller(9143) on 2010-01-03 16:19:56 (Show Source):
You can put this solution on YOUR website!
You should be making two equations with two unknowns.
You substituted 3w for w instead of 3w for e
Don't use x for multiplication sign
Use the asterisk above the number 8
Also we usually put numbers before letters
3w not w3
w3 can be confused for w^3
Mathematics is a language and has rules just like English and Spanish
and it has its own vocabulary and word order.
e=3w
(e+4)=2(w+4)
substitute 3w for e
3w+4=2w+8
subtract 2w from both sides
subtract 4 from both sides
w=4
e=3*w=12
check
12+4=2(4+4)
16=2*8
16=16
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Linear-systems/249847: On a canoe trip, Rita paddled upstream (against the current) at an average speed of 2 mi/h relative to the riverbank. On the return trip downstream (with the current), her average speed was 3 mi/h. Find Rita's paddling speed in still water and the speed of the river's current.
1 solutions
Answer 185559 by richwmiller(9143) on 2010-01-03 16:04:01 (Show Source):
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