Miembros: Melody

Zoldyck:
A solid consist of a cylinder of a base radius of 2.5cm and a height of 8cm, with its base place on top of a cuboid with dimensions 11cm by 7 cm by 3cm.
1. What is the volume?
2. What is the total surface area?

The more normal name for a cuboid is a rectangular prism.
Do you know how to find the volume of a rectangular prism?
Do you know how to find the volume of a cylinder?
If you do then just add them together and you will have the volume.

For surface area I will assume that both shapes are solid. eg there is a top one the cylinder, and a bottom on the cuboid.
So all you have to do is find the area of each of the 6 sides of the cuboid and the curved surface of the cylinder and the lid of the cylinder.
You need to think about the bottom of the cylinder. Is this area included? Has it already been included with the cuboid? You will need to think about this.
I would like you to think about what I have written and then ask more specific questions.
I am happy to help more but you just need to think first. Maybe put a toilet roll on top of a tissue box and think about what you have.

Melody2 ene 2014

+118691

Tim:
How do I solve the formula 30000000=10^x

Whenever the unknown is a power (or exponent) you will need to use logarithms.
(The only exceptions will be very simple examples like 10 ^x=10000)

Anyway for your question you need to take the log of both sides.
You can use any base but for this example base 10 would be easiest.

log(30000000) = log 10 ^x

then you will use the log identity log(a ^b) = b * log (a)

you see if you can work it out from there.

Melody2 ene 2014

#45

+118691

That's fine Random. I'm really glad that you are hanging in here.
Your answers were all what I wanted except you didn't put n= or r= and you left out the dollar sign.
I want you to put n and r because i am going to relate what you are learning now to your compound interest question and there is an n and an r in that formula.

I'm going to look at the answer a little differently. And I want you to use the picture to help understand what I am trying to tell you.

I want 3 dozen bananas.
The bananas are bundled in nets of 2 (2 bananas per net) The cost is $4.08 for a dozen.
6 nets of 2 bananas.JPG
12 / 2 = 6 That is, 6 nets make up a dozen, that 6 is the magic number for this question!

Now r is the cost for 1 net. And all 6 nets together are $4.08. So
r = $4.08 / 6 = $0.68 (for 1 net)
PLEASE NOTE THAT I DID NOT WORK OUT HOW MUCH 1 BANANA WAS FIRST.

Now, n is the number of nets that I need to buy.
I want 3 dozen bananas and 6 nets make up 1 dozen so
n = 3 x 6 = 18 nets.
PLEASE NOTE THAT I DID NOT WORK OUT HOW MANY BANANAS I WANTED FIRST.
-----------------------------------------------------------------------------------------------------------------------------------
Okay, I'm going to stick to the same bananas
This time I want 5 dozen bananas
Same questions as before.
a) how many bananas per net ? You already know that the answer is 6. Use the 6 in the working for both the next questions.
b) Let r be the price per net. Find r
c) Let n be the number of nets that you will be buying. Find n

The working is the most important bit

Melody2 ene 2014

+118691

Guest:
0.8 recurring times 100

0.888888888........ x 100

You have to move the decimal point 2 places (because there are 2 zeros in 100) in the direction to make the number bigger (because if you multiply by 100 any number gets bigger)

So you tell me, what is the answer?

Melody2 ene 2014

#16

+118691

3, 7, 7, 25, 75, 100 with magic number 735

I know that this one works.

Come on people!
This one is not that hard. Won't someone give it a go?
Remember, You get 5 points just for showing interest!
Hint: What is 7 x 100 ?

Melody2 ene 2014

+118691

I had a great time watching all the fireworks on Sydney Harbour last night. (New Year's eve) They were fantastic!

I have to go home to Springfield, Illinois soon, (Homer is hungry, Lisa is lonely and Bart is into mischief. - they all miss me and I miss them!)
I have Maggie with me, she's too little to be away from her Mom, but she misses her siblings
I'm also worried that Homer might forget to feed Santas Little Helper.
Santas Little Helper.JPG

But its been fun staying with Melody in Sydney, Australia.

I've had a great holiday. Ands I am glad I could share it all with you

Marge.
fireworks on sydney harbour 2014.jpg

Melody1 ene 2014

#15

+118691

Melody31 dic 2013

#13

+118691

Most (almost all) have answers, but some don't. I haven't found and answer for this yet. (which is a little unusual)
The nearest that I have so far is 735 (1 too big)
I take it that you haven't found an answer yet?

Melody31 dic 2013

#11

+118691

Yes, but you chose hard numbers! I usually get these pretty easily but I haven't solved this one yet.
Anyway, if no one gets it then the person who makes the closest number wins.

I've never been to the USA, but I think Los Angeles would be beautiful, and a lot of fun. (so long as there wasn't a big earth quake!)

Melody31 dic 2013

+118691

Hi Jedithious,
I was pondering the same question.
Did you make up the numbers without thinking about the result?
If you did then I think that you could play but maybe you should leave it at least a couple of hours before you post your solution.
Just to let other people have a chance first. Does that sound reasonable?

If anyone would like to voice an objection or an oppinion please do so.
If you do you'll get 5 points for your participation!
Melody.

p.s. Where did you go? I love travelling!

PUZZLE 3
3,7,7,25,75,100 Magic number 734
This is Jedithious's Puzzle and no one has solved it yet!

Melody31 dic 2013

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