Ermm anyone know anything about maths?

[ruthless_villain]

Hi guys, well my maths test is coming up soon and my teacher gave me a specimen paper to do and well im stuck, im sure its a basic question but cant get my head around it, well here goes

The rule for finding the next term in a different sequence is to multiply the previous term by 2 and then add on a, where a is an integer

The first term is 8 and the fourth term is 127

8 ....... ....... 127

work out the value of a

well thanks for any help, and if no one can help then it was worth a shot, bye!

 

[Sapsh]

Hi guys, well my maths test is coming up soon and my teacher gave me a specimen paper to do and well im stuck, im sure its a basic question but cant get my head around it, well here goes

The rule for finding the next term in a different sequence is to multiply the previous term by 2 and then add on a, where a is an integer

The first term is 8 and the fourth term is 127

8 ....... ....... 127

work out the value of a

well thanks for any help, and if no one can help then it was worth a shot, bye!

Here it goes:

There are 4 numbers:

8, b, c, 127

according to the specified rule, b = 8*2 + a = 16 + a

similarly, c = b*2 + a = 32 + 2a + a = 32 + 3a

then 127 = c*2 + a = 64 + 6a + a = 64 + 7a

therefore 7a = 63 and a = 9

I wish my exam tomorrow would be this kind of stuff...

 

[ruthless_villain]

thanks a lot dude, what exams u got?

 

[Sapsh]

Quantum information theory xD its the last exam for me, EVER!

 

[ruthless_villain]

Quantum information theory xD its the last exam for me, EVER!

good luck mate, and thanks a lot

 

[dugdiamond]

Here it goes:

There are 4 numbers:

8, b, c, 127

according to the specified rule, b = 8*2 + a = 16 + a

similarly, c = b*2 + a = 32 + 2a + a = 32 + 3a

then 127 = c*2 + a = 64 + 6a + a = 64 + 7a

therefore 7a = 63 and a = 9

I wish my exam tomorrow would be this kind of stuff...

correct!!!!

good luck with your exams tommorrow !!!

but, it is simple logic...

if x * 2 + a = 127, then a is an odd number

also, if it takes three numbers multiplied by two to complete a sequence, then the number must be less than 2 * 2 * 2 = 16 and greater than 2 * 2 = 4,

and since we are adding a whole number (integer), it must <=15 and =>7 (because 2 + 2 + 2 + 1 = 7)

so, the logical numbers for a would be 15, 13, 11, 9... simulate

a = 9

8 * 2 + 9 = 25 (the second number in the sequence is 25)

25 * 2 + 9 = 59 (the third number in the sequence is 59)

59 * 2 + 9 = 127

 

[Sapsh]

then the number must be less than 2 * 2 * 2 = 16

last time I checked 2^3 was 8...

So your method is not really working. I can see where you are coming from, although once you deduce the range, you suggest testing them all, which is not the quickest way to do this problem. This is a loop (as in programming), which would only be required if you would have 4 arbitrary numbers with a changing condition between them. And even if numbers would be different (different quantity of them too) it is always recommended to deduce an analytic solution, which could then be extended to accommodate all possible changing parameters. Just checked your profile, I see that you code, so you should see sense in what I'm saying and that your solution is not efficient.

And check ruthless_villain's profile, you'll realise that the solution of the type you provided would not be required from him.

And yeah, cheers guys for wishing me luck! Same to you ruthless_villain.

 

[dugdiamond]

last time I checked 2^3 was 8...

So your method is not really working. I can see where you are coming from, although once you deduce the range, you suggest testing them all, which is not the quickest way to do this problem. This is a loop (as in programming), which would only be required if you would have 4 arbitrary numbers with a changing condition between them. And even if numbers would be different (different quantity of them too) it is always recommended to deduce an analytic solution, which could then be extended to accommodate all possible changing parameters. Just checked your profile, I see that you code, so you should see sense in what I'm saying and that your solution is not efficient.

And check ruthless_villain's profile, you'll realise that the solution of the type you provided would not be required from him.

And yeah, cheers guys for wishing me luck! Same to you ruthless_villain.

lol

i am a programmer

and without writing the code on the page (which would baffle most people) i tried the explain my methodologies without any

and yes it was a typo.... i meant 2 squared ... squared

but, anyway... he got the answer

 

[Chaney579]

Ahh yes according to my handy dandy calculator this is correct

, Should invest in one. Like a good 5 US dollars at the local store

 

[dugdiamond]

Ahh yes according to my handy dandy calculator this is correct

, Should invest in one. Like a good 5 US dollars at the local store

lmfao - or... use the one in windows (it has always had a calcy) - it is in accessories

 

[ruthless_villain]

thanks for the effort dug and thanks again to sapsh

 

[Sapsh]

2 ruthless_villain: no worries

2 dugdiamond: I know it was a typo, was just joking, but forgot to put a smiley in, lol

 

[Ya93sin]

LOL, I need 55% in C4 next monday to get an A, but 85% for an A*. Stupid grading system.

You can get all B's at AS-Level, and still potentially get an A*.

 

[ruthless_villain]

LOL, I need 55% in C4 next monday to get an A, but 85% for an A*. Stupid grading system.

You can get all B's at AS-Level, and still potentially get an A*.

What exam board are your school using

 

[Calico]

Good luck with your exams everyone... i take it the ones doin A level will be the last lot to get the £3000/year fees at university?

 

[Root]

Good luck dude, I already finished my exams! (IGCSE)

 

[Ya93sin]

What exam board are your school using

MEI (Published by OCR)

 

[Ya93sin]

Good luck with your exams everyone... i take it the ones doin A level will be the last lot to get the £3000/year fees at university?

I think its just under £3.5k (I should really know the figure off by heart though, applied for student finance only a couple weeks ago :S )

But yeah we are very lucky people.

 

[Calico]

I think its just under £3.5k (I should really know the figure off by heart though, applied for student finance only a couple weeks ago :S )

But yeah we are very lucky people.

yeah its around £3,300. 9K is a bit much imo... AND you cant pay off your debt in large chunks with the new rules... you have to pay it back slowly from your income over hundreds of years (or however long it takes

)

Luckily for me... I'm just leaving uni! Final piece of work to go in this monday.. and I'm done!

What course are you doing?

 

[Ya93sin]

yeah its around £3,300. 9K is a bit much imo... AND you cant pay off your debt in large chunks with the new rules... you have to pay it back slowly from your income over hundreds of years (or however long it takes

)

Luckily for me... I'm just leaving uni! Final piece of work to go in this monday.. and I'm done!

What course are you doing?

LOL lucky you, end of an era

I get a placement year in the 3rd year which is compulsory, average salary is £15k they said, and I have a part time job at Tesco, so can switch, so I should just about be affording everything except a bit of accommodation.

I wonder who will end up paying for that

Gotta get the grades first though

Good luck dude, I already finished my exams! (IGCSE)

I would happily swap positions with you