Logical Reasoning - Number Series - Discussion

Discussion Forum : Number Series - Type 1 (Q.No. 16)
Directions to Solve
In each series, look for the degree and direction of change between the numbers. In other words, do the numbers increase or decrease, and by how much

16.
Look at this series: 80, 10, 70, 15, 60, ... What number should come next?
20
25
30
50
Answer: Option
Explanation:
This is an alternating addition and subtraction series. In the first pattern, 10 is subtracted from each number to arrive at the next. In the second, 5 is added to each number to arrive at the next.
Discussion:
83 comments Page 8 of 9.

Uday said:   8 years ago
Thanks to all for providing this explanation.

Kripal Sharma said:   8 years ago
Thanks to all for this explanation.

Abhiram said:   9 years ago
Thank you all for explaining this.

Neha said:   9 years ago
80,_70_60_50_(decrease series.) in 10 table.

10 15 20 25( increase series) in 5 table.

Mannu kumar said:   9 years ago
80-10=70
70-10=60
60-10=50 and so on...
NW
10+5=15
15+5=20
20+5=25 and so on.

Now your final series is 80, 10, 70, 15, 60, 20, 50, 25.

Sushree sonali said:   1 decade ago
Thanks sundar. Your explanation really helps me to know the answer.

Ria sen said:   9 years ago
Need more explanation.

Chirag modi said:   9 years ago
Now, I understand this, Thank you all.

Nandini said:   9 years ago
Thanks for explaining the logic to find the answer. It's really helpful.

Shadab Akhtar said:   9 years ago
First series;

80 - 70 = 10.
10 + 60 = 70.
70 - 55 = 15.
15 + 45 = 60.
60 - 40 = 20.

And, alternate series;

-70 + 60 = -10.
+60 - 55 = +5.
-55 + 45 = -10.
+45 - 40 = +5 and so on....

Hope this answer clarify all your doubt.


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