Logical Reasoning - Number Series - Discussion
Discussion Forum : Number Series - Type 2 (Q.No. 1)
Directions to Solve
Look carefully for the pattern, and then choose which pair of numbers comes next.
1.
28 25 5 21 18 5 14
Answer: Option
Explanation:
This is an alternating subtraction series with the interpolation of a random number, 5, as every third number. In the subtraction series, 3 is subtracted, then 4, then 3, and so on.
Discussion:
126 comments Page 1 of 13.
Hema said:
1 year ago
diff(28 - 25) = 3,
5
diff(21-18) = 3,
5,
diff(14-x) = 3.
Then, 14-3=x=>x=11.
5
Hence 28 25 5 21 18 5 14 11 5 is the correct order.
5
diff(21-18) = 3,
5,
diff(14-x) = 3.
Then, 14-3=x=>x=11.
5
Hence 28 25 5 21 18 5 14 11 5 is the correct order.
(123)
AMAN NAIK said:
2 years ago
@All.
Consider 3 number pairs.
28 25 5 21 18 5 14.
28 - 7 = 21.
25 - 7 = 18.
5.
21 - 7 = 14
18 - 7 = 11
5.
So, 11, 5 in the next number of the series.
Consider 3 number pairs.
28 25 5 21 18 5 14.
28 - 7 = 21.
25 - 7 = 18.
5.
21 - 7 = 14
18 - 7 = 11
5.
So, 11, 5 in the next number of the series.
(88)
Xiyoz said:
3 years ago
Skip the 5.
28-3=25 5.
25-4=21.
21-3=18 5.
18-4=14.
14-3=11 5.
So the answer is (11 5).
28-3=25 5.
25-4=21.
21-3=18 5.
18-4=14.
14-3=11 5.
So the answer is (11 5).
(69)
Sheshadri DB said:
2 years ago
The random number 5 is every third number.
Subtraction series 3,4,3,4,3,4,3,4.
hence
28-3=25 -> 28,25,5.
25-4=21 -> 21.
21-3=18 -> 21,18,5.
18-4=14 ->14.
14-3=11 ->14,11,5.
11,5 is the answer.
28, 25, 5, 21, 18, 5, 14, 11, 5.
Subtraction series 3,4,3,4,3,4,3,4.
hence
28-3=25 -> 28,25,5.
25-4=21 -> 21.
21-3=18 -> 21,18,5.
18-4=14 ->14.
14-3=11 ->14,11,5.
11,5 is the answer.
28, 25, 5, 21, 18, 5, 14, 11, 5.
(39)
Mussa khan said:
3 years ago
Thanks all for explaining.
(35)
Saurabh Singh said:
3 years ago
INTERPOLATION here means simply including the number without logic.
28 25 5 21 18 5 14.
Here 5 is used as a median you can say remove the 5's
28 25 (diff 3),
21 18 (diff 3),
14 ? (diff 3)( ?=11).
Then the next number is 5 because of interpolation.
28 25 5 21 18 5 14.
Here 5 is used as a median you can say remove the 5's
28 25 (diff 3),
21 18 (diff 3),
14 ? (diff 3)( ?=11).
Then the next number is 5 because of interpolation.
(34)
Aatif said:
3 years ago
Actually, 5 is common. So 5 remains unchanged in the whole series.
28-3 =25.
25-4= 21.
21-3=18.
18-4=14.
14-3=11.
So the answer is 11 and 5 as common.
11 5.
28-3 =25.
25-4= 21.
21-3=18.
18-4=14.
14-3=11.
So the answer is 11 and 5 as common.
11 5.
(14)
Arosej said:
2 years ago
Good solution, Thanks, I can understand.
(10)
Ajit said:
2 years ago
Thanks all for explaining it.
(9)
Sk ali said:
2 months ago
28-3 = 25,
25-4 = 21,
21-3 = 18,
18-4 = 14,
14-3 = 11 ( 5 is a random number).
25-4 = 21,
21-3 = 18,
18-4 = 14,
14-3 = 11 ( 5 is a random number).
(9)
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