Logical Reasoning - Number Series - Discussion
Discussion Forum : Number Series - Type 2 (Q.No. 7)
Directions to Solve
Look carefully for the pattern, and then choose which pair of numbers comes next.
7.
17 17 34 20 20 31 23
Answer: Option
Explanation:
This is an alternating subtraction series with repetition. There are two different patterns here. In the first, a number repeats itself; then 3 is added to that number to arrive at the next number, which also repeats. This gives the series 17, 17, 20, 20, 23, and so on. Every third number follows a second pattern, in which 3 is subtracted from each number to arrive at the next: 34, 31, 28.
Discussion:
33 comments Page 1 of 4.
Rajib Das said:
1 decade ago
17, 17, 34, 20, 20, 31, 23, .....What number should be next?
____a1____ _b1_ ____a2___ _b2_ ____a3___ _b3_
17 17 34 20 20 31 23 (23*?) (28*?)
0 0 0
a1=17-17=0 and a1-a2=17-20=-3
b1=20-20=0 and a2-a3=20-23=-3
So, a3=0=23-23*
Again, b1-b2=34-31=+3
So, b2-b3=+3=31-28* Ans:Next numbers are 23,28.
____a1____ _b1_ ____a2___ _b2_ ____a3___ _b3_
17 17 34 20 20 31 23 (23*?) (28*?)
0 0 0
a1=17-17=0 and a1-a2=17-20=-3
b1=20-20=0 and a2-a3=20-23=-3
So, a3=0=23-23*
Again, b1-b2=34-31=+3
So, b2-b3=+3=31-28* Ans:Next numbers are 23,28.
Sundar said:
1 decade ago
Given 17 17 34 20 20 31 23 ....
17 17 - Series 1 [Add 3; 14+3 = 17]
-- 34 - Series 2 [Sub 3; 37-3 = 34]
20 20 - Series 1 [Add 3; 17+4 = 30]
-- 31 - Series 2 [Sub 3; 34-3 = 31]
23 23*
-- 28*
26 26
-- 25
29 29
-- 22
... continued.
The stared text 23*, 28* is the required answer for the given series.
Hope this help you. Have a nice day!
17 17 - Series 1 [Add 3; 14+3 = 17]
-- 34 - Series 2 [Sub 3; 37-3 = 34]
20 20 - Series 1 [Add 3; 17+4 = 30]
-- 31 - Series 2 [Sub 3; 34-3 = 31]
23 23*
-- 28*
26 26
-- 25
29 29
-- 22
... continued.
The stared text 23*, 28* is the required answer for the given series.
Hope this help you. Have a nice day!
Hely said:
7 years ago
The one pattern i used to solve this series is:
17 + 17 = 34 (17=prime number).
34 - 14 = 20 (17-3=14).
20 + 11 = 31 (11=prime number) (skipping a prime number after 17).
31 - 8 = 23 (11-3=8).
23 + 5 = 28 (5=prime number) (skipping a prime number after 11).
17 + 17 = 34 (17=prime number).
34 - 14 = 20 (17-3=14).
20 + 11 = 31 (11=prime number) (skipping a prime number after 17).
31 - 8 = 23 (11-3=8).
23 + 5 = 28 (5=prime number) (skipping a prime number after 11).
(3)
Priyanka said:
1 decade ago
Ohhhhho very simple Technique : Take two series like as:
1st series: 17,17....20,20.... nw 23,23..... that means add +3
2nd series: 34....... 31.... now 28... that means subtract -3
Simple combination of two series....
So ans will be 23,28.
1st series: 17,17....20,20.... nw 23,23..... that means add +3
2nd series: 34....... 31.... now 28... that means subtract -3
Simple combination of two series....
So ans will be 23,28.
(1)
SREEKANTH said:
1 decade ago
IN EASY WAY.
17 17 34 20 20 31 23 __ __
Solving,
(17 17) 34 (20 20) 31 (23 ?) ?
In brackets same terms
And remaining are 34 31 _? here difference 3. In the way 34 31 28.
ANS : 23 28.
17 17 34 20 20 31 23 __ __
Solving,
(17 17) 34 (20 20) 31 (23 ?) ?
In brackets same terms
And remaining are 34 31 _? here difference 3. In the way 34 31 28.
ANS : 23 28.
Somasaikiran said:
9 years ago
first of all the given sequence is;
17 17 34 20 20 31 23.
Take 17 17 as series 1,
Take 31 as a series 2,
First add 3 to 17 17+3=20 for series 1,
And then sub 3 from 34 in series 34-3=31.
17 17 34 20 20 31 23.
Take 17 17 as series 1,
Take 31 as a series 2,
First add 3 to 17 17+3=20 for series 1,
And then sub 3 from 34 in series 34-3=31.
Deena V said:
1 decade ago
17-17= 0
17-34= -17
34-20= +14
20-20= 0
20-31= -11
31-23= +8
23-(x)= 0(i.e x =23)
23-(x)= -5(i.e x=28),
After zero, 3 is continuously subtract and polarity has been changed at this series
17-34= -17
34-20= +14
20-20= 0
20-31= -11
31-23= +8
23-(x)= 0(i.e x =23)
23-(x)= -5(i.e x=28),
After zero, 3 is continuously subtract and polarity has been changed at this series
Komal said:
1 decade ago
17 17 Series 1
34 is Series 2
We have to add 3 in series 1 i.e 17+3=20
After this we have to subtract 3 from Series 2 i.e 34-3=31
Then answer is 20+3=23 and 31-3= 28
Answer is 23 28
34 is Series 2
We have to add 3 in series 1 i.e 17+3=20
After this we have to subtract 3 from Series 2 i.e 34-3=31
Then answer is 20+3=23 and 31-3= 28
Answer is 23 28
Ali said:
5 years ago
17 17 34 20 20 31 23:
(17 17) (34) (20 20) (31) (23).
1:17 20 and 23.
2:34 and 31.
Two different series . In 1:(+3) and 2:(-3);
So the answer =23 28.
(17 17) (34) (20 20) (31) (23).
1:17 20 and 23.
2:34 and 31.
Two different series . In 1:(+3) and 2:(-3);
So the answer =23 28.
(8)
Saurabh said:
1 decade ago
17
17+17=34 nothing is subtracted here
20
20+20=40, 9 is subtracted here =31
23
23+23=46,18 is subtracted here = 28
so option e is correct
17+17=34 nothing is subtracted here
20
20+20=40, 9 is subtracted here =31
23
23+23=46,18 is subtracted here = 28
so option e is correct
(1)
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