[robertsqueen]

Here is the question:
Our sun is 93 million miles away... the speed of light travels at 186 thousand miles per second, how long does it take the speed of light to get from the sun to the earth? Show me the answer in minutes.

[galactus]

All you have to do is divide 93 million by 186000, then divide that result by 60. That'll be the number of minutes for light to get to the Earth from the Sun.

[Dr D]

I think the original post may have been looking for a logical way to solve such a problem without error. A simple concept called "unit cancellation" works in all cases. The start of the problem is given in miles, and you are seeking an answer of minutes. Just keep multiplying the start by a fraction that always equals one. Then cancel out like units that are found on top with ones found on the bottom until you get an answer in the desired unit. Be sure to multiply the numbers associated with the unit: 93 M miles x 1 sec/186K miles x 1 min/60 sec. Do the multiplication and division, and cancel like units on top and bottom will give you the answer in minutes. I hope this is what you were asking for.

[robertsqueen]

Thank you guys so much... you saved my life and grade lol

[robertsqueen]

Could you show me how to do it? I am confused I tried but I have to show my work. I got 8.3 seconds... but I have to show my work...

[galactus]

No, it is not 8.3 seconds.


I thought it was just explained about as easy as can be explained.

Here's an exampe of the same thing. If you can walk 3 mph and it is 6 miles from where you are to your house, how long to get home? Same thing, only bigger numbers.

You can't calculate that? May I ask what grade you're in?

I will divide by 1000 to simplify things a bit. So we don't have too big of numbers to work with. Always do that if you can.

[robertsqueen]

I am in college... but I have a math learning disability, I have my whole life. I figured it out its 8.3 minutes... I didn't mean to put seconds.

[galactus]

The same time you posted, I edited my post. You are correct. Very good. You get a cookie:) . A math disability? That's called calculia. Same as Dyslexia, only with math instead of reading. May I ask why and what confounds you so much about basic arithmetic? The thing to do is the same as learning to swim; Throw you right in the deepest hole. We'll start with Calculus and move on to Differential Geometry and Lie Algebra.


I am just teasing. Post whenever you have a quandary and I'll see if I can help. Since you're shortcoming is math, are you good at reading, spelling, and English-type subjects?

[robertsqueen]

I am sorry that I jumped down your throat.. I am just having a really hard time in math. Just everything about math confuses me. I am awsome at other subjects... I excel. I had learning disabiities growing up because I was born half deaf and didn't speak until I was six. I overcame all of my disabilities but math. I just don't understand it. I don't understand converting units. If you are converting units going up the scale like from a kilometer to a meter do you divide. And if you are going from a mile to an inch do you multiply? It just all confuses me.

[galactus]

Everyone has a different brain. Try relaxing and thinking about it. Suppose you had 325 meters and wanted it in kilometers. One thing nice about the metric system is that it's in 10's . That would be 0.325 kilometers. It would be less than 1, because 325 is less than 1000.

10 millimeters in a centimeter. 10 centimeters in a decimeter, 100 centimeters in a meter, 1000 metes in a kilometer. Think about the prefixes if that easier. Centi- means 100, kilo means 1000, milli means 1000th, etc.

If you had 2.5 kilometers, then that would be 2500 meters, since there are 1000 meters in a kilometer.

The Old English system is a different animal. It is not consistent. It comes from way back in the Middle Ages when things were measured in a wacky way. For instance, 1 acre is the amount of ground a team of oxen could plow in a day; 1 inch was the width of the kings thumb; one yard was the length of the kings arm from his chest to the tip of this finger(something like that).
It goes on and on. The only reason it's still used is because we're used to it, not because it's more practical. As a matter of fact, if I am not mistaken, the US and Liberia are the only countries which still use the Old English system. Personally, I can use either. Doesn't matter.

Let's do the inches to miles thing. With the metric system, we know there are 1000 meters in a kilometer. But, with our old timey way, you have to know there are 5,280 feet in a mile.

There are 12 inches in a foot, so there are 63,360 inches in a mile. That's because 5280*12=63360.

If you have anymore questions, feel free to post.


Good luck and take care,
Cody

[robertsqueen]

I know and I am sorry as I explained I am just having a really hard semister... but I do appriacate the help.

[galactus]

Everyone has their 'crosses to bear' in school. Mine was English-type things.

I can spell, but I always hated that grammar business. I ain't got no english penchant. Give me math anyday.

[Dr D]

Dear robertsqueen, the problem is not with you, but with the crummy math instruction that you have received in school. My math education went as far as calculus, which I have long since forgotten. When my kids were little, they brought home their grammar school math homework, and I said "What in the hell is this". Some years later, one of my son's friends was struggling with a college algebra class. After one afternoon with me, he said "this is easy s***." If you can find a tutor who is patient, and does not use the math jargon that teachers rely on, you will wonder why you ever found it hard. Hang in there and the light will come on.

[robertsqueen]

Thank you Dr. D.

[MarioFLH07]

How Many Centimeters Are In An Inch

[galactus]

2.54