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 2 of 4.
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)
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.
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
Mahesh said:
1 decade ago
17+17 = 34-0 = 34.
20+20 = 40-9 = 31.
Now verify option,
23+23 = 46-18 = 28 So answer is 23, 28.
20+20 = 40-9 = 31.
Now verify option,
23+23 = 46-18 = 28 So answer is 23, 28.
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.
Baidhar said:
1 decade ago
17+3 = 20
17+3 = 20
34-3 = 31
20+3 = 23
20+3 = 23
31-3 = 28
Answer is 23 28.
17+3 = 20
34-3 = 31
20+3 = 23
20+3 = 23
31-3 = 28
Answer is 23 28.
PANERI RIYA R said:
10 years ago
17 17, 17, 20, 20 differences between 3 20+3 = 23.
2 34, 31 difference between 31-3 = 28 answer 23 28.
2 34, 31 difference between 31-3 = 28 answer 23 28.
Aditya vamsi said:
9 years ago
For every two consequent numbers 3 is added to the next one and three is subtracted from the preceding number.
Rohit said:
9 years ago
Very nice trick @Priyanka.
(1)
Satheeshkumar said:
9 years ago
17 + 3 = 20,
17 + 3 = 20,
34 - 3 = 31,
17 + 6 = 23,
17 + 6 = 23,
34 - 6 = 28.
17 + 3 = 20,
34 - 3 = 31,
17 + 6 = 23,
17 + 6 = 23,
34 - 6 = 28.
(1)
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