Infosys
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by*
SIVARAMAN SURESH
on
21-Mar-2016 19:12

Find the next term of the series?

1,4,9,18,35,?

options are

a)41

b)49

c)66

d)54

solution:

Formula (x*2+2,+1,+0,-1,-2)

1,4,9,18,35,?

options are

a)41

b)49

c)66

d)54

solution:

Formula (x*2+2,+1,+0,-1,-2)

2nd no.: 1x2+2=4

3: 4x2+1=9

4: 9x2+0=18

5: 18x2+(-1)=35

6: 35x2+(-2)=68

the 6th no. is 68

but why there is no 68 in the options ????

3: 4x2+1=9

4: 9x2+0=18

5: 18x2+(-1)=35

6: 35x2+(-2)=68

the 6th no. is 68

but why there is no 68 in the options ????

SkillRack
on
21-Mar-2016 23:15

This question was asked in Infosys test.
Here as your logic does not yield any one of the given options, we need to try to come up with a different logic which will yield one of the given options (As our ultimate aim is to answer the question and score marks :) )
Nth term = Previous three terms + 4
so ? = 9+18+35+4 = 66

TANMAY PRAMANICK
on
22-Mar-2016 01:02

If addition is the way to solve the problem, then why the series is given in such a manner. The solution doesn't match the series given in order.

SkillRack
on
22-Mar-2016 10:48

@Tanmay We cannot question the way the question is framed. We need to find the best possible solution with the given premise. The solution 66 is one of the given options. As it is previous three terms, the logic is applicable only from 4th term.
If you can come up with some other logic and get any of the other options 41 or 49 or 54, then we can call the question as confusing or not proper one.

J VIGHNESH
on
25-Mar-2016 22:12

2^1-1=1
2^2-0=4
2^3+1=9
2^4+2=18
2^5+3=35
so next would be
2^6+6=68

J VIGHNESH
on
25-Mar-2016 22:12

sorry its,2^6+4=68

G BHARGAV
on
28-Mar-2016 13:11

68

DARSHAN DAYAL SURI
on
28-Mar-2016 14:50

4th digit=3rd digit+ 2nd digit + 1st digit + 4
5th digit=4th digit+ 3rd digit + 2nd digit + 4
similarly,
6th digit=5th digit + 4th digit+ 3rd digit + 4
therefore,6th digit=35+18+9+4=66
c)66, Is the correct option.

VINAYAK A MODI
on
29-Mar-2016 17:34Accepted Solution

1,4,9,18,35,? so 35+31=66(can also be 68)
+3,+5,+9,+17,next +31(can also be 33)
+2,+4,+8 next +14(can also be 16)
+2,+4,next+6(can also be 8)
both 68 and 66 are possible answers as 66 is in option c)

MOHD AKRAM ANSARI
on
1-Apr-2016 10:04

ASHUTOSH KUMAR
on
1-Apr-2016 11:12

It should be 66,by the logic of adding the last three digit.

S.JAYA KRISHNA KUMAR
on
3-Apr-2016 14:15

Ans:68

HARI
on
6-Apr-2016 20:04

1,4,9,18,35,?
2*1-1=1
2*2 0=4
2*2*2 1=9
2*2*2*2 2=18
2*2*2*2*2 3=35
2*2*2*2*2*2 4=68
ans=68

HARI
on
6-Apr-2016 20:06

1,4,9,18,35,?
2*1-1=1
2*2 0=4
2*2*2 1=9
2*2*2*2 2=18
2*2*2*2*2 3=35
2*2*2*2*2*2 4=68
ans=68

G BHARGAV
on
11-Apr-2016 12:47

66

A PRANAY DEEPU REDDY
on
11-Apr-2016 16:43

Good question

Aishwarya
on
12-Apr-2016 10:51

54

SAHAJ MAHESHWARI
on
29-Apr-2016 04:21

ans 54
adding sequence of prime no.s

ABDUL HALEEM KHAN. S
on
20-May-2016 14:40

66 is answer.
(9+4+1)+4=18
(18+9+4)+4=35
(35+18+9)+4=66

DIVA
on
13-Jun-2016 13:02

68

THAVAGURU M
on
23-Jun-2016 12:59

66

BOOPATHI RAJA A
on
27-Jun-2016 16:22

66

DUGGINENI SAI DIVYA
on
28-Jun-2016 14:05

66

DUGGINENI SAI DIVYA
on
28-Jun-2016 14:06

68

DILLIBABU K
on
2-Jul-2016 20:33

c). 66