Logical Reasoning - Number Series - Discussion
Discussion Forum : Number Series - Type 1 (Q.No. 19)
Directions to Solve
In each series, look for the degree and direction of change between the numbers. In other words, do the numbers increase or decrease, and by how much
19.
Look at this series: 8, 6, 9, 23, 87 , ... What number should come next?
Answer: Option
Explanation:
8 x 1 - 2 = 6
6 x 2 - 3 = 9
9 x 3 - 4 = 23
23 x 4 - 5 = 87
87 x 5 - 6 = 429 ...
Discussion:
116 comments Page 10 of 12.
Arj said:
1 decade ago
Is there any other way to solve the series?
Amit said:
1 decade ago
I have solved all series problems its very easy only two problems are moderate.
Gaurav Sharma said:
1 decade ago
So easy but starting point is very tough.
Nityusha said:
1 decade ago
Any other simpler way?
The Helpful Brit said:
1 decade ago
General form is X(n+1) = (X (n)*n) - (n+1) ). Where X(n) is the term number in the series, X (n+1) is the subsequent term and n is the element position aka as index.
All algebraic terms will always represent integer values.
X(n); n(X (n)*n)-(n+1)) = X(n+1).
X(1) = 8; n = 1((8)*(1))-(2)) = 6.
X(2) = 6; n = 2((6)*(2))-(3)) = 9.
X(3) = 9; n = 3((9)*(3))-(4)) = 23.
X(4) = 23; n = 4((23)*(4))-(5)) = 87.
X(5) = 87; n = 5((87)*(5))-(6)) = 429.
Therefore.
X(6) = 429; n = 6((429)*(6))-(7)) = 2567.
All algebraic terms will always represent integer values.
X(n); n(X (n)*n)-(n+1)) = X(n+1).
X(1) = 8; n = 1((8)*(1))-(2)) = 6.
X(2) = 6; n = 2((6)*(2))-(3)) = 9.
X(3) = 9; n = 3((9)*(3))-(4)) = 23.
X(4) = 23; n = 4((23)*(4))-(5)) = 87.
X(5) = 87; n = 5((87)*(5))-(6)) = 429.
Therefore.
X(6) = 429; n = 6((429)*(6))-(7)) = 2567.
Narendra Padhan said:
1 decade ago
It is the best method of develop your knowledge.
Atul said:
1 decade ago
25*02+15+54-25*15/25.
Suresha c n said:
1 decade ago
Is any other easy way except mentioned above all?
Suranjika Muni said:
1 decade ago
This is good process through which one will improve his/her mental ability.
Ram babu said:
1 decade ago
One said that by adding the first 3 no's we can get 4th and adding next 3 no's we get 6th but it's wrong. Because if we follow this how we can get 2nd and 3rd no's.
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