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alice22
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This sequence cropped up in an IQ test.
I can't for the life of me work out the next term, any ideas?
3, 8, 18, 30, 70, ?,
I can't for the life of me work out the next term, any ideas?
3, 8, 18, 30, 70, ?,
Lord Crc said:The difference between the second and the third number is twice that of the difference between the second and the first. Thus 70-30 = 40, and 2*40+70 = 150.
Xitami said:[itex]R(n)=\frac{1}{15}\left(-45(-1)^n+36(-2)^n+63(2)^n-(3)^n-8(-3)^n\right)[/itex]
R(5)=174
The functions Q(x) and P(x) that I posted are number patterns Chaz. They might not be the pattern that you want, but they most definitely are number patterns in the usual sense.The Chaz said:You all seem to have missed that this is from an IQ TEST.
Yes, you can write an infinite list of polynomials with these roots, but that's not the question.
FIND.
THE.
PATTERN!
uart said:The functions Q(x) and P(x) that I posted are number patterns Chaz. They might not be the pattern that you want, but they most definitely are number patterns in the usual sense.
uart said:However 30 is NOT equal to 18 + 2 x 10
And 70 is NOT equal to 30 + 2 x 12
I'm not sure how you managed to overlook that?
Dickfore said:To justify my solution with more than just "looking at the stars", I will offer this reasoning.
A linear homogeneous recursion of order p:
[tex]
x_{n + p} + c_{1} \, x_{n + p -1} + \ldots + c_{p - 1} \, x_{n + 1} + c_{p} \, x_{n} = 0
[/tex]
has a particular solution of the form: ...
The Chaz said:You make a good point. There is a subjective element to this, which is where the hardline polynomial advocates and I part ways. I once saw a justification for 31 as the next in the sequence:
1,2,4,8,16,...
And it made sense, but you'd better not put that on the IQ test!
shinkyo00 said:Here's my solution.
Sequence: 5, 8, 18, 30, 70, ?
Phenomenal said:This is being WAY overanalysed in my opinion. In terms of this being an IQ question the logical answer I can understand being 150.
3 x 2 + 2 = 8
8 x 2 + 2 = 18
18 x 2 - 6 = 30, does not follow rule.
30 x 2 + 10 = 70
70 x 2 + 10 = 150
Here we have to make the assumption that it's going to be +10 again to follow the previous. If anyone wants to reason on why we wouldn't assume that I'd welcome it. I see this as being the only logical way of looking at the question.
uart said:So what would the next term after 150 be Phenomenal. Would it follow the "rule" or not follow the rule? It's not such a good rule if it's only sometimes followed.
Phenomenal said:The point is you're only asked for the NEXT number. It doesn't ask you to work out the next several.. Excuse my use of the term rule, you're correct. What I am implying is that this is the only 'pattern' that really applies and thus 150 makes perfect sense.
This is one question in an IQ test as already said, it's not expected that the situation is overanalysed using the previous calculations that have already been done so far in this thread.
A number sequence IQ question is designed to test an individual's ability to recognize patterns and sequences in numbers. It is often used as a measure of cognitive ability and problem-solving skills.
To solve a number sequence IQ question, you need to carefully examine the given sequence of numbers and look for any patterns or rules that govern the sequence. Once you have identified the pattern, you can use it to predict the next term in the sequence.
Some common strategies for solving number sequence IQ questions include looking for arithmetic or geometric patterns, checking for alternating or repeating patterns, and using mathematical operations such as addition, subtraction, multiplication, or division on the given numbers.
No, there is no specific formula for solving number sequence IQ questions. Each question may have a different pattern or rule, so it is important to carefully analyze the given sequence and use logical reasoning to determine the next term.
Yes, number sequence IQ questions can be solved without any mathematical knowledge. While some questions may involve basic mathematical operations, others may rely on visual or logical patterns that can be identified without any mathematical background.