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+33669

purple:
:?: Puzzled, need some help! Will you please show the work on coming up with the answer?

1) 10kilohms divided-by ( 2.2kilohms + 10kilohms)

2) 250millivolts divided-by 50microvolts

3) 1megawatt divided-by 2kilowatts

I do think I did these problems wrong, I lost. Please will someone give me the help and by showing how you retrieved the answer? Thank-you so much.

1) The items on the top and bottom are all in the same unit, namely kilohms, so the result is just the dimensionless ratio 10/(2.2+10), or 10/12.2

10/12.2

2) A millivolt is one thousandth of a volt so 250 millivolts is 250*10 ^-3 volts. A microvolt is a millionth of a volt so 50 microvolts is 50*10 ^-6 volts. Now you simply divide: 250*10 ^-3/(50*10^-6)

250*10^-3/(50*10^-6)

3) A megawatt is 10 ⁶ watts. A kilowatt is 10 ³ watts. See if you can take this one from there.

AlanMar 31, 2014

Will you please show the work, I'm puzzled !

1) 10kilohms / (2.2kilohms + 10kilohms)

2) 250millivolts / 50microvolts

3) 1megawatt / 2kilowatts

I thank the person that will help me with these math problems, :0)

GuestMar 31, 2014

+5478

A wheel has a radius of 2 and 1 third feet. About how far does it travel if it makes 60 complete revolutions? Use 22/7 for 3.14

First, find the diameter of the wheel, which is twice the radius.
2*2 1/3 = 4 2/3

Then use this to find the circumference:
4 2/3 * 22/7
= 14 2/3

This is the length of one revolution.
Now multiply it by 60 to get the length of 60 revolutions.
14 2/3 * 60

=880 feet.

kitty<3Mar 31, 2014

+118741

The angle at the top of Alan's picture is the angle of depression.
The angle at the bottom is equal because they are alternate angles on parallel lines.

MelodyMar 31, 2014

+118741

Serjio:
Give an example where you put observational learning into effect. What did you observe and what did you end up doing (or not doing)?

Hi Serjio,
I have observed that when it rains the washing gets wet so I have learned to take if off the line. Now do I get a lollypop?

MelodyMar 31, 2014

+118741

reinout-g:
Bertie:
E5 must be 12.
It's not prime so it can't be at B5, it's divisible by 6 so can't go in C4 and it will be too big to go in A4 or D4.

Even though I'm currently at a point where I know you are right, at this point it still could've been at A3.

Be aware that in *15* they only mean the square which is diagonally at the right-bottom.

I am with reinout.
Why can't A3 be 12 Why does it have to be E5?
I'm sorry, I think that you have made a retraction and added a new answer.
I didn't notice.

So at this point E5 does not have to be 12 but B5 has to be 11.
I won't look at your logic - I will think about it first.
Thank you Bertie.

MelodyMar 31, 2014

Mar 30, 2014

+130586

15x^2 - 6x - 9 = 0
Let's divide through by three to make this a little easier - maybe.
5x^2 - 2x - 3 = 0
Let's see if this will factor
(5x + 3) (x - 1) = 0

Yep...that works okay......Can you finish it from here???

CPhillMar 30, 2014

+130586

I'm not sure exactly what you're asking for, but it appears to be either (4^5)* x = 15 or 4^(5x) = 15
Oh well....doesn't matter......I'll do both and you can take your choice

First.......
(4^5)* x = 15
(1024) * x =15
solving for x by dividing both sides by 1024, we have
x =

15 / 1024

Second................. (I think this is the one you're really interested in)
4^(5x) = 15
Take the log of both sides
log(4)^(5x) = log(15)
By the property of logs we can write
(5x)*log(4) = log (15)
Divide by log(4) on both sides
(5x) = log (15) / log (4)
Now divide by 5 on both sides
x =

log(15)/(5*log(4))

And there you go..........

CPhillMar 30, 2014

+201

First subtract 5x -3x and get 2x so if 2x equals 4, 4/2 =2

So x=2

mathcalcMar 30, 2014

+33669

CPhill:
Use the tangent here. Let x represent the distance the fire is from the tower.

tan (19° ) = 26 / x

x =

26 / tan(19 )

≈ 76 ft.

Here with a picture and a few more steps thrown in for good measure!
distance.PNG

AlanMar 30, 2014

+130586

Use the tangent here. Let x represent the distance the fire is from the tower.

tan (19° ) = 26 / x

x =

26 / tan(19 )

≈ 76 ft.

CPhillMar 30, 2014

+33669

purple:
express each number in engineering notation: 2.35*10 to the power of 5
7.32*10 to the power of 7
1.333*10 to the power of 9

Engineering notation usually means expressing the exponent of the power of ten in multiples of 3. So:

235*10 ³
73.2*10 ⁶
1.333*10 ⁹

AlanMar 30, 2014

+130586

¡Para servirle!

CPhillMar 30, 2014

+130586

Trap.JPG

Sorry, just messing around with this new app !!!

CPhillMar 30, 2014

Gracias Amigos cxcx

GuestMar 30, 2014

+130586

Well...if he spent 3/4 of his money, he must just have 1/4 left.

So, 4 times what he has left must be what he started with.

Thus....4 * 12 = $48

CPhillMar 30, 2014

+118741

ohnonotmath:
Hello Melody!

0.15(1-x) = 0.3 + 0.33x
0.15 - 0.15x = 0.3 + 0.33x
(then I add 0.15x to both sides and subtract 0.3 from both sides)
0.15 - 0.3 = 0.15x + 0.33x
-0.15 = 0.48x
-0.15/0.48 = x
x = -0.3125 This is an exact answer, there is no need to round off.
?

Thanks for showing me how to set up the problem. Again it's one of those things I use to know but forgot over the years

So you are a mature aged student? What are you studying?
Have you collected your welcome message?
Melody

MelodyMar 30, 2014

+23

Hello Melody!

0.15(1-x) = 0.3 + 0.33x
0.15 - 0.15x = 0.3 + 0.33x
(then I add 0.15x to both sides and subtract 0.3 from both sides)
0.15 - 0.3 = 0.15x + 0.33x
-0.15 = 0.48x
-0.15/0.48 = x
x = -0.312
?

Thanks for showing me how to set up the problem. Again it's one of those things I use to know but forgot over the years

ohnonotmathMar 30, 2014

+118741

ohnonotmath:
0.15 = 0.3 + x(0.33)
1-x

I hope this comes out right. the 0.3 + x(0.33) is all over 1-x

Hi ohnonotmath,
Your explanation of the question is good and leaves little room for misinterpretaion but I will show you how you could have presented this problem.

0.15 = (0.3 + x(0.33)) / (1-x)

0.15 = (0.3 + 0.33x) / (1-x)
At this point you need to recognise that you cannot divide by 0.
therefore 1-x cannot = 0 --> x cannot = 1
Now, multiply both sides by (1-x) to get rid of the fraction.

0.15(1-x) = 0.3 + 0.33x
Can you take over from here? I will check your final answer if you want me to.

MelodyMar 30, 2014

#87

+118741

Hi all,
Another quiet day. There were some great answers from Bertie, CPhill, I like Serena and dophysics. Thank you.
Stu also provide another useful link post on his Top Free Site thread. Thanks Stu.
Enjoy what is left of your week end.
Melody.

MelodyMar 30, 2014

+118741

bump

MelodyMar 30, 2014

+118741

Thanks for that great answer Chris,
I just felt like drawing a picture.
If you want to play with GeoGebra, this might be a good one for you to try and reproduce.
Melody.
140330 trapezium.JPG

MelodyMar 30, 2014

+118741

cydneeyx3:
Katie spent $7.24 on lunch at the mall. She bought a CD for $13.78 and a pair of jeans for $24.71. While she was at the mall, one of her friends paid her back $20 that she had borrowed from Katie. If katie now has $49.27, how much money did she take with her to the mall?

You could do it the other way around too.

Katie has $49.27 but her friend just gave her $20 so before that she had $29.27. As CPhill already worked out she had spent $45.73 at the mall.
So when she first entered the mall she must have had $29.27 + $45.73

MelodyMar 30, 2014

+118741

gotenks0906:
:oops: 5x=3x+4

Take 3x off both sides - that will result in all the xes being on the same side.
There will be a number in front of the x.
You have to work put how to get rid of that number (with +, -, x, or divide) And then you will have to do it to both sides.
Then you will have your answer.

MelodyMar 30, 2014

how do you solve it

GuestMar 30, 2014

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