Math Is Fun Forum

  Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °

You are not logged in.

#226 Help Me ! » LCMultiple » 2024-05-26 03:07:10

paulb203
Replies: 1

Three buses, bus A, bus B and bus C all use the same bus stop.
A runs every 10 mins
B runs every 12 mins
C runs every 14 mins
All three are the bus stop at 11am
What time will all three buses next be at the bus stop

Q. What does ‘runs every 10 mins’ mean?

#227 Re: Help Me ! » Inequalities on Graphs » 2024-05-25 02:18:09

Thanks, Bob.

Here's the kind of thing we're doing;

https://www.mathsgenie.co.uk/resources/6-inequalities-regions.pdf

I'm on question 5 at the moment and finding it tricky

#228 Help Me ! » Error Intervals » 2024-05-24 22:38:17

paulb203
Replies: 4

Sally used her calculator to work out the value of a number y
The answer on her calculator display began;
8.3
Complete the error interval for y
*
Does ‘began’ imply there is more to come after the 3?
Or could 8.3 be the answer on her calculator (could it begin AND END with 8.3?)

I’m thinking it implies it could be either, i.e, it might be 8.3, it might be more, so...
The answer on her calculator could be;
8.3
8.31
8.301
8.27685
8.999999999999999994
Etc, etc.
So...
The error interval is;
Equal to or greater than 8.3
Less than 8.4
?

#229 Help Me ! » Simplifying Algebraic Fractions » 2024-05-23 05:59:25

paulb203
Replies: 2

Can the following fraction be simplified further?
Numerator;   2(x+3)
Denominator; 2(x+1)

#230 Re: Help Me ! » Number Zero » 2024-05-22 09:46:51

Why does zero times anything equal zero?

I guess x times y means how many lots of y you have

2 times y means you have 2 lots of y

10 times y means you have 10 lots of y

Zero times y means you have zero lots of y

You have no lots of y

You have no y

#231 Re: Help Me ! » Edexcel Maths GCSE Higher Tier » 2024-05-22 09:33:25

I'm curious to have another look at the questions, but also;

We've been given a handout of expected topics in the next two papers, given what was in the first paper. It's from 1st Class Maths. But I don't know how reliable it is. And given the huge number of topics they've starred as very likely to unlikely (five stars down to one star) it looks like they're not just going on what topics have already come up. There was only around 20 questions on the first paper so there must be some other criteria for predicting what's likely to come up.
E.g. under 2 stars (pretty unlikely) there are around 40 topics listed.

#232 Re: Help Me ! » Edexcel Maths GCSE Higher Tier » 2024-05-22 09:29:01

Thanks, Bob.
Yeah, our teacher said somebody usually puts it online.

#233 Help Me ! » Inequalities on Graphs » 2024-05-22 09:26:54

paulb203
Replies: 3

Does anybody else hate these?

Is it just me, or are they messy/awkward/UGLY/unsatisfying?

#234 Help Me ! » Edexcel Maths GCSE Higher Tier » 2024-05-21 22:33:10

paulb203
Replies: 5

Is Paper 1, and the mark scheme, (May 24), available anywhere, now that the exam has taken place?

I've looked online but couldn't find it anywhere.

#235 Help Me ! » Inequalities on Graphs » 2024-05-21 02:02:47

paulb203
Replies: 2

I came across the following inequality in this context;

x ≤ 6-2y

My instinct was to rearrange it to have y on the left hand side thus;

y ≤ -(1/2x) +3

Should I have bothered?

I guess I'm used to seeing it that way.

#236 Re: Help Me ! » Simplifying Algebraic Fractions » 2024-05-20 21:48:30

Thanks, Bob.

The question said;

"Simplify fully"

So which is simpler; (2x+3) /(x-3)?

or; 4x+6 / (x-3)?

#237 Help Me ! » Simplifying Algebraic Fractions » 2024-05-19 23:07:14

paulb203
Replies: 4

I simplified an algebraic fraction to; 4x+6/(x-3)

But the answer given was 2(2x+3)/(x-3)

They hadn't expanded 2(2x+3) to 4x+6

Did I go too far, or did they not go far enough?

#239 Science HQ » Is our planet dying? » 2024-05-19 04:03:10

paulb203
Replies: 4

Is the planet (Earth) dying?
Was it ever alive?
Before the first soil, before the first moss, or moss-like plant, or blue-green algae - basically before the first life forms that would attach themselves to the surface of the Earth, what was the surface like?
Was it smooth, like an enormous (almost) spherical stone? What was it’s composition, approximately?
And, back to the top, if every life form on Earth went extinct and all the corpses (including the plant ‘corpses’) decomposed, to dust (?) would the planet be just as it was 4-5 billion years ago before life arose on it?

#240 Re: Help Me ! » Exponents / Algebra / Equations » 2024-05-18 22:50:14

"As x can anything you can equate the non x bits and separately the x bits"

x is a variable, yeah?

Are b and c not variables? Can they not be anything?

I know you've shown them to be 27,3, here, but how do I know when first looking at the problem that b and c are different from x (in terms of the latter being able to be anything)?

Is there no permuation of values where b and c could equal something different?

#241 Help Me ! » Surface Area » 2024-05-18 21:38:19

paulb203
Replies: 2

Surface Area
If the surface area of solid shape is 4cm^2 what can we infer about the shape?
Not a sphere (pi would lead to decimals)?
Same for cones and cylinders?
Pyramid?
Or does 4cm^2 have a square ‘ring’ to it? Should we be thinking cube/cuboid?

Also, at GCSE level (UK), or at any level for that matter, does 'solid shape' refer to 'straightforward' solid shapes, as opposed to the 3d versions of compound shapes?

#242 Re: Help Me ! » Norman Window » 2024-05-18 09:58:19

Blue tit babies. Sounds great.

#244 Re: Help Me ! » Equation of a tangent to a circle » 2024-05-17 06:39:53

Great answer. Thanks, Bob.

I think I'm getting there, understanding the first part. I'll need to come back for another look. And another smile

#245 Re: Help Me ! » Probability of Rapture Event » 2024-05-17 06:25:13

Keep_Relentless wrote:

If you believe the Bible 100%, then the probability of a rapture occurring is 100%. The only question is when.

If you don't believe the Bible 100%, then I would expect the probability of a rapture to be getting lower with every day that passes without a rapture, and every day that passes with no independent confirmation of miracles.


K_R

Is the probability of the above not x/y, regardless of what one believes?

Is the probability of 36 appearing on single zero (unbiased) roulette wheel (with no shenanigans from the croupier/player, etc) is 1/37 regardless of the beliefs of any onlooker/s?

#246 Re: Help Me ! » Probability of Rapture Event » 2024-05-17 06:17:13

Keep_Relentless wrote:

They say anything is possible because there is no logical contradiction if it were to happen. There is no logical contradiction in a miracle occurring. No scientific theory can prove a miracle could never happen. It can only show that it is very improbable - since it has not occurred in many repetitions/trials. But that does not get the probability to zero, it just gets it very small.

Of course if a naturalistic view is correct where the laws of nature are absolutely inviolable then the probability is zero. But I don't know how you could establish with literally 100% confidence that this is the case.

So, basically, anything that is conceivable is possible. That's how it looks to me at least.

Thanks. So is 'Anything is possible', in this context, shorthand for, 'Anything is possible, LOGICALLY speaking'? Which may be followed up by, 'Whether anything is PHYSICALLY possible is another matter.'?

#247 Re: Help Me ! » Exponents / Algebra / Equations » 2024-05-17 06:11:21

Bob wrote:

bx^6 = (3x^2)^c

What are we meant to do with this expression?

Bob

Doh! I forgot to add the crucial part; find out the value of b, and the value of c.

#248 Re: Help Me ! » Exponents / Algebra / Equations » 2024-05-17 06:10:03

KerimF wrote:

To avoid confusion or for clarity, I used to add '*' always to denote a product.
For example
bx^6 = (3x^2)^c becomes:
b*(x^6) = [3*(x^2)]^c

Now we can also write it as:
b*(x^6) = (3^c)*[(x^2)]^c
b*(x^6) = (3^c)*[x^(2*c)]
etc...

Thanks, KerimF

#249 Re: Help Me ! » Equation of a tangent to a circle » 2024-05-16 05:53:16

Bob wrote:

Yes, sorry I should have said (x-a)^2.  But the no "-2xa" still applies.

Bob

Thanks, Bob.

What does, "The -2xa term is missing" mean?

We expanded (x-a)^2 and got x^2-ax-ax+a^2 which simplifies to x^2-2ax+a^2

And then..?

#250 Help Me ! » Exponents / Algebra / Equations » 2024-05-16 05:40:14

paulb203
Replies: 12

bx^6 = (3x^2)^c

First off;

How to tackle (3x^2)^c?

If c was, say, 2, then we would have; (3x^2)(3x^2), yeah?

Which would = 9x^4, yeah?

Can we do; (3x^2)^c = 3x^2*c? (multiply the exponents, 2*c)

Which would, if c was 2, = 3x^4

No? Because we already got = 9x^4?

*

And then with the whole equation; what can we do to both sides?

The only thing I can think of is to divide both sides by b, but that looks awkward - making the right hand side a fraction with b on the bottom!

Board footer

Powered by FluxBB