May 7, 2013

How do you average out grades? we home school and I need to know what average they hold as of now?

There is 345 points possible and the points made is 343.. so what is that in a averaged grade?

No. Take the number of points possible and divide it INTO the points earned, then multiply by 100. So, 343/345 x100 = your percentage score. Then you the parent, teacher, and administrator of the school, decide on what your grading scale is, such as 94-100 is an A, 88-93 is a B or whatever you decide it is.

How do you answer this math question on percentage?

I’m trying to figure out these questions for my math homework, but i’m not quite sure on how to figure them out.

A population grows by 5.7% each year. By what percentage does it grow each month? A population declines by 0.9% each year. By what percentage does it decline each decade?

1.057=e^(k12)

k=.00462

e^(.00462*1)=1.00463

.00463 x100=.463%

.91=e^(k*1)

k=-.-09431

e^(-.09431*10)=.389419

1-.389419=.610581*100=61.1%

What could be the best option for a full manual not-DSLR camera?

Yes, trying to avoid bulkiness of DSLRs but retaining the full manual control and the best lens possible… A nice Zoom will help also but is not a must, since most of my subjects stand between 9-30 ft. I’ve heard a lot about the Nikon P7000 and the Canon G12, but I’m not sure if these cameras would fall short for a 30 ft subject.
Thank you for every suggestion.

For a nice manual 4x barrel zoom in a compact digital camera there is only one answer. Check out the Fujifilm X10:

http://fujifilm-x100.com/fujifilm-x10-best-all-in-one-compact-digital-camera-with-zoom/

The Fuji X10 features 4x Optical Zoom (28-112mm) and Bright Lens (F2.0-F2.8) and Full Manual Controls in a robust, magnesium alloy, rangefinderesque body.

Whats a good camera for fast shooting and accurate lighting?

Im searching for an advanced p and s camera that can capture photos with good lighting indoors and outdoors, and that can take fast shots without flash. Can anyone recommend anything?
I was looking for something between 100 and 200 bucks.

That depends on how much you want to spend. With few except, P&S cameras have small sensors, which can really inhibit low light shooting performance.

For standard P&S, your best bet is one with a fast lens, like the Olympus XZ-1. This is a premium P&S camera that you can pick up right now for as little as \$200, since they’ve announced its successor, the XZ-2. You could wait for the XZ-2, but you’ll pay more and it is supposed to have the same lens. Others include the Panasonic Lumix LX7, and Canon G15.

Then there are then P&S cameras with larger sensors – the Fuji X series (X10, X100 & XF1), the Canon GX1 and Sony RSX100. Of the Fuji X100, Sony RSX100 & Canon GX1, the Canon scored the best in low-light performance by a noticeable margin, though the Fuji XF1 might be better, not sure.

Then there is the new outlier – The Sony RSX1 with a full frame sensor. This will almost certainly take your best pictures in low light of any P&S, but at it’s current price you could pick up most APS or Micro 4/3rds cameras and a very fast lens, and possibly have some money left to spend on other lenses too.

Also note, as the sensor gets larger, so does the camera in most cases, so take that into consideration if pocketability is a concern.

EDIT: Noting your price restriction, the XZ-1 is the way to go: http://www.amazon.com/Olympus-Digital-Camera-3-Inch-Monitor/dp/B004HO59LK/ref=sr_1_1?ie=UTF8&qid=1352494163&sr=8-1&keywords=olympus+xz-1

All of the cameras I mentioned are significantly more than \$200, most much, much more, even the XZ-1 would normally be a lot more if it hadn’t been discounted so much recently.

What is the percent water by weight in this hydrate?

Cobalt (II) Chloride is commonly obtained from chemical supply houses as as hydrate with the formula CoCl2 * 6 H2O. An analysis showed that 25.0 g of this hydrate contains 11.3 g of water.

From the formula. FW of hydrate = 237.9
Contribution from 6 H2O = 108
(108/237.9 )x100 = 45.4%

From experimental data (11.3/25 )x 100 = 45.2%
Pretty good agreement.

How do you assign a number value to a word in excel?

I want to make an excel sheet and enter cpt manually and have a column with rvu that is generated automatically. In short, how do I have a code and assign a number value to it so when I type in the code, the value will appear in the next cell and I can total it.

You can use VLOOKUP, LOOKUP, INDEX/MATCH combination. It really depends on how you set up your data.

If you create a table somewhere with your cpt and rvu values, and if these are the only 2 columns of data, you can use LOOKUP if the cpt values are in sequential order. If not, then you would use VLOOKUP.

Here are the basic setups for each:

=LOOKUP(A2, X1:X100, Y1:Y100)

looks for the value you enter in cell A2 in the range X1:X100, then returns the corresponding value in Y1:Y100.

=VLOOKUP(A2, X1:Y100, 2, FALSE)

Does the same as above, X1:Y100 being a 2 column lookup table, and the 2 means you want to return the value in the 2nd column of said lookup table.

Hope this helps.

How to do linearization with lots of words?

A surveyor is standing 30 ft from the base of a building. She measures the angle of elevation to the top of the building to be 75º. How accurately must the angle be measured for the percentage error in estimating the height of the building to be less than 4%?

The solution involves some calculus so I hope you are at that level:

The formula for the height of the building is:

h = (30ft)*tan(theta)

If you differentiate h with respect to theta you get:

dh/dtheta = 30*sec^2(theta)

Now in terms of differentials this can be expressed as:

dh = 30*sec^2(theta)*dtheta

Here the differential dh represents the error in h that would result from an error in theta, dtheta

The percent error in h is dh/h (x100) so:

dh/h = 30*sec^2(theta)*(dtheta)/h = 30/cos^2(theta)*(dtheta)/h

substituting in the formula for h you get:

= 30/cos^2(theta)*(dtheta)/[30*tan(theta)]

=dtheta/[cos^2(theta)*tan(theta)]

=dtheta/[cos(theta)*sin(theta)]

solving for dtheta:

dtheta = (dh/h)*cos(theta)*sin(theta)

= (0.04)*(0.2588)*(0.9659)

= 0.0100 degrees maximum allowable error in the angle measurement to have less than 4% error in height calculated.

Hope this helps

How much should I sell my product to retailers for?

I bake a cake that yields 16 slices and costs me £13 in total to make.
I reckon that the sandwich shop/deli I plan to sell it to can get £1.70/£1.80 per portion.

How much should I ask the shop owner to buy my cake for?

Hey, nice little maths question.

Your costs are £13, and they can sell for £1.70 = £27.2.

However what they sell it at shouldn’t really factor into your sums – they may not sell all the slices, they might have to discount… Also bear in mind they are the guys doing the marketing and selling your cake – they have staff costs, VAT, taxes, rates etc etc to pay.

For me, making 40% margin is happy days, but I’d settle for 30% at the moment.

Lets say – for simplicity all the costs for making a cake (heating the oven, bit of a margin for cost increases) is £15.

Gross Margin = your selling price – cost / your selling price X100.

So, lets say you sell the cake for £18, what kind of margin will that be?

18 – 15 = 3 (price – cost)
3 / 18 = 0.1666 (price – cost / price)
0.1666* 100 = 16% margin.

Too low?

20-15 = 5
5/20 = 0.25
0.25 * 100 = 25% margin. Which seems reasonable.

Of course, lovely excel spread sheets with “what” and “ifs” are one thing, it really depends on what they want to pay. £20 seems right, but you know not to go under £18…

Good luck!