xr_craig

iTrader: (2)

Algebra help please

(3,4,5,8,9) > (8,11,14,19,22)

Whats the function that maps the input to the output?

It's for my little cousin and i'm fucked if i know

mk3matt

i think its...

2N + (N-1) sorta thing?

so 3 x 2 = 6 + 2 = 8
so 4 x 2 = 8 +3 = 11
so 5 x 2 = 10 + 4 = 14


tbh i int got a clue...got a U at as level maths hehehe

xr_craig

iTrader: (2)

See i managed to get formulas like that, but they don't work for 8 or 9 as

8 x 2 = 16 + 7 = 23

It's been bugging me for ages

BM08

Im not even going to attempt that, im shit at sums

Chip

iTrader: (3)

I cant see a pattern for those numbers off hand TBH.

Have you deffo typed it in right before anyone puts too much effort into it?


Ps

2N + (N-1) = 3N - 1


Just to make it a bit simpler to see that one isnt it matt, as that would make 9 -> 26

xr_craig

iTrader: (2)

Yes mate, definately correct

CharlieSaff

Tried but I think you've copied it wrong mate

CharlieSaff

Whoops

Chip

iTrader: (3)

I cant work it out then.

The gaps initially get bigger as the numbers increase, and then get smaller as the number increases later on, which rules out most simple functions.

EIL132

Input 3 Function 5 Output 8, Input 4 Function 7 Ouput 11, etc, etc. The function is the number that makes the output from the input.

Lee Reynolds

its bollox i know that much

xr_craig

iTrader: (2)

Thats what got me mate, it makes no sense.

Plus its 100% right unless its a print error in the book

focusv8

All trying too hard:

3 + 5 = 8
4 + 7 = 11
5 + 9 = 14
8 + 11=19
9 + 13=22

Spot the pattern.

,

Chip

iTrader: (3)

Not really, cause I cant work out from that what the input of 6 would give TBH

How do you propose to express that as a function?

focusv8

It's not asking for 6

.

RWD_cossie_wil

iTrader: (9)

I will never understand the point of Algebra ... seems to exist just because it does, no use to anyone

Chip

iTrader: (3)

Its asking for a function definition, i dont see what yours is TBH

Punkie

this is what got me too....

how old is your cousin? 21 doing a degree?

focusv8

If its junior school it'll be,

(3,4,5,8,9) + (5,7,9,11,13) = (8,11,14,19,22)

.

Chip

iTrader: (3)

thats gay, thats not even vaugely a proper function definition

xr_craig

iTrader: (2)

12 doing year 8 maths

Chip

iTrader: (3)

lmao, then i think maybe we are looking too far into it, lol, the answer above is probably right.

xr_craig

iTrader: (2)

I thought that may be the case as the rest were really straight forward. But can't figure it out. I've just given up now

StephenC

Theres 5 numbers in each 'array'. If N= the number in that sequence then the 3rd input (5) is N=3, the fourth number (8) is N=4.
The relationship between input and output is 2N+3. Giving
(2N)+3
N=1 so Output = (2*1)+3=5 plus the input number of 3 gives output 8
N=2 so output = (2*2)+3=7 plus the input number of 4 gives output 11
N=3 so output = (2*3)+3=9 plus the input number of 5 gives output 14
N=4 so output = (2*4)+3=11 plus the input number of 8 gives output 19
N=5 so output = (2*5)+3=13 plus the input number of 9 gives output 22

best I can do, sorry
the 6th input would be 12 and the ouput would be 37 by the way

Chip

iTrader: (3)

Thats a nonsense, what reasoning do you have for the 6th number being 12?

It could be 6 giving 21 and it still be equally valid and still follow the same rule IMHO

StephenC

at midnight it seemed right
its not about finding the 6th,7th,8th numbers, its about what you need to do to the number given as an input to get the output from those shown (5 inputs mapped to 5 outputs) and that rule is as above

Ryan_3

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