Aptitude - Odd Man Out and Series - Discussion
Discussion Forum : Odd Man Out and Series - Pick Wrong No. (Q.No. 5)
Directions to Solve
Find out the wrong number in the given sequence of numbers.
5.
1, 2, 6, 15, 31, 56, 91
Answer: Option
Explanation:
1, 1 + 12 = 2, 2 + 22 = 6, 6 + 32 = 15, 15 + 42 = 31, 31 + 52 = 56, 56 + 62 = 92
Last number of given series must be 92 not 91.
Discussion:
22 comments Page 1 of 3.
Harsh said:
1 decade ago
Only the sum of first and last number is divisible by 5.
Dhivya said:
1 decade ago
Can someone explain this clearly ?
Kumar said:
1 decade ago
2-1,6-2,15-6,31-15,56-31,91-56
1,4,9,16,25,45
last number is clearly wrong because those are perfect squares
1,4,9,16,25,45
last number is clearly wrong because those are perfect squares
Sonutalwani said:
1 decade ago
1 + (1*1) = 2.
2 + (2*2) = 6.
6 + (3*3) = 15.
15 + (4*4) = 31.
31 + (5*5) = 56.
56 + (6*6) = 92 (91 is wrong number).
2 + (2*2) = 6.
6 + (3*3) = 15.
15 + (4*4) = 31.
31 + (5*5) = 56.
56 + (6*6) = 92 (91 is wrong number).
Ravi Agola said:
1 decade ago
Actual answer by easy method.
1 is odd then two are even 2, 6 then two are odd 15, 31 then two are even 56, 91 but here 91 is odd so answer. Is 91 which we same get with previous method.
1 is odd then two are even 2, 6 then two are odd 15, 31 then two are even 56, 91 but here 91 is odd so answer. Is 91 which we same get with previous method.
(1)
Sikkanthar said:
1 decade ago
In this problem they are adding the result with square value of the natural numbers.
I mean.
1,
1(result) + (1*1) = 2.
2(result) + (2*2) = 6.
6(result) + (3*3) = 15.
15(result) + (4*4) = 31.
31(result) + (5*5) = 56.
56(result) + (6*6) = 92.
Now we are getting 92 not 91.. So 91 is the wrong number of the given.
I mean.
1,
1(result) + (1*1) = 2.
2(result) + (2*2) = 6.
6(result) + (3*3) = 15.
15(result) + (4*4) = 31.
31(result) + (5*5) = 56.
56(result) + (6*6) = 92.
Now we are getting 92 not 91.. So 91 is the wrong number of the given.
Rajesh said:
1 decade ago
@Kumar.
Your concept is OK. But same time you took the wrong concept.
First minus 1 by 2.
Then minus 6 by 2 how is it correct? OK now you understand.
But your thing is good.
Your concept is OK. But same time you took the wrong concept.
First minus 1 by 2.
Then minus 6 by 2 how is it correct? OK now you understand.
But your thing is good.
Umang said:
1 decade ago
2-1 = 1*1
6-2 = 2*2
15-6 = 3*3
31-15 = 4*4
64-31 = 5*5
But 91-56 = 6*6 is not happening.
So 91 is odd no.
6-2 = 2*2
15-6 = 3*3
31-15 = 4*4
64-31 = 5*5
But 91-56 = 6*6 is not happening.
So 91 is odd no.
Sam said:
1 decade ago
10 teams participating in national football league. If each team plays the other team two times, the total number of games the league will play is.
Beda said:
1 decade ago
In question 31 is the only prime number. So why the answer is not 31?
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