Logical Reasoning - Number Series - Discussion
Discussion Forum : Number Series - Type 1 (Q.No. 1)
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
1.
Look at this series: 2, 1, (1/2), (1/4), ... What number should come next?
Answer: Option
Explanation:
This is a simple division series; each number is one-half of the previous number.
In other terms to say, the number is divided by 2 successively to get the next result.
4/2 = 2 2/2 = 1 1/2 = 1/2 (1/2)/2 = 1/4 (1/4)/2 = 1/8 and so on.
Discussion:
182 comments Page 1 of 19.
Jeevagan said:
1 decade ago
It's not that big issue.!
First look at the series then start relating between them.
Ex:
Here in the series 2, 1, 1/2, 1/4,....
Just by first analysis we can conclude that next no. To 1st no is half time to it, and the logic is checked with next successive no.
Step 1:- 2,
Step 2:- 2, 1==>2, 2/2 (1),...
Step 3:- 2, 1, 1/2==>2, 2/2 (1) , 1/2 (1/2),....
Step 4:- 2, 1, 1/2, 1/4==>2, 2/2 (1), 1/2 (1/2) , (1/2) /2 (1/4),...
First look at the series then start relating between them.
Ex:
Here in the series 2, 1, 1/2, 1/4,....
Just by first analysis we can conclude that next no. To 1st no is half time to it, and the logic is checked with next successive no.
Step 1:- 2,
Step 2:- 2, 1==>2, 2/2 (1),...
Step 3:- 2, 1, 1/2==>2, 2/2 (1) , 1/2 (1/2),....
Step 4:- 2, 1, 1/2, 1/4==>2, 2/2 (1), 1/2 (1/2) , (1/2) /2 (1/4),...
Lisa Price said:
1 decade ago
I need help finding the next number in the series to:
1. 18,81,27,36,63?
2. 1/64,1/32,1/16,1/8,1/4,1/2?
3. 36,37,39,42,46,51?
4. 8,4,2,1,.5,.25,.25?
5. 2,4,6,5,7,9,8?
6. 154,77,81,78,39,43,40?
7. 1/2,1/4,1/3,1/6,1/5?
8. 2,3,4,8,9,10,20,21,22?
9. 2,5,14,41,122?
10. 15,18,54,57,171?
11. 18,81,27,72,36,63?
12. 1/64,1/32,1/16,1/8,1/4,1/2?
13. 36,37,39,42,46,51?
14. 2,4,6,5,7,9,8?
15. 154,77,81,78,39,43,40?
1. 18,81,27,36,63?
2. 1/64,1/32,1/16,1/8,1/4,1/2?
3. 36,37,39,42,46,51?
4. 8,4,2,1,.5,.25,.25?
5. 2,4,6,5,7,9,8?
6. 154,77,81,78,39,43,40?
7. 1/2,1/4,1/3,1/6,1/5?
8. 2,3,4,8,9,10,20,21,22?
9. 2,5,14,41,122?
10. 15,18,54,57,171?
11. 18,81,27,72,36,63?
12. 1/64,1/32,1/16,1/8,1/4,1/2?
13. 36,37,39,42,46,51?
14. 2,4,6,5,7,9,8?
15. 154,77,81,78,39,43,40?
Saiteja Hanumandla said:
9 years ago
According to the question.
Look at this series: 2, 1, (1/2) , (1/4) , . What number should come next?
Principle we need to follow this. This is a simple division series; each number is one-half of the previous number. 1 * 1/2 = 1/2.
2 * 1/2 = 2/2 =1.
1/4 * 1/2=1/8 so the answer is 1/8.
Let me know is there any mistake feel free to tell me because me also pure in maths.
Look at this series: 2, 1, (1/2) , (1/4) , . What number should come next?
Principle we need to follow this. This is a simple division series; each number is one-half of the previous number. 1 * 1/2 = 1/2.
2 * 1/2 = 2/2 =1.
1/4 * 1/2=1/8 so the answer is 1/8.
Let me know is there any mistake feel free to tell me because me also pure in maths.
Rajpal singh said:
1 decade ago
Here why not multiple each no. By 2. Here first and second no. Multiple by 2 and third, fourth, . , . , . Not multiple by 2 its only divided by 2 why? while third no. Is same put.
Logical reasoning want same process in each no.
Logical reasoning want same process in each no.
Shubhi said:
1 decade ago
Very easy just half and divided by 2 like in:
Step 1: Take a no 4 itself.
4/2 = 2.
Step 2: After that half the number, so 4/2 = 2 and then divide by 2.
2/2 = 1.
Step 3:
1/2 = 1/2.
(1/2)/2 = 1/4.
(1/4)/2 = 1/8 and so on.
Step 1: Take a no 4 itself.
4/2 = 2.
Step 2: After that half the number, so 4/2 = 2 and then divide by 2.
2/2 = 1.
Step 3:
1/2 = 1/2.
(1/2)/2 = 1/4.
(1/4)/2 = 1/8 and so on.
Sandeep Kumar said:
7 years ago
Let me tell you.
As you know that term of geometric progression.
a/r, a, ar, ar2.
So if we write in this form ar, a, a/r, a/r2.
Where a =1 (Constant) and r=2 (Common Ratio).
i.e it can be written 2, 1, 1/2, 1/4, 1/8.
As you know that term of geometric progression.
a/r, a, ar, ar2.
So if we write in this form ar, a, a/r, a/r2.
Where a =1 (Constant) and r=2 (Common Ratio).
i.e it can be written 2, 1, 1/2, 1/4, 1/8.
Joe mama said:
2 years ago
22-1 = 21 + 2 = 23
23-1 = 22 + 2 = 25.
In this number series, 1 has been subtracted with the first given number, then again 2 has been added with the (subtracted) obtained number.
So, the right answer will be 25.
23-1 = 22 + 2 = 25.
In this number series, 1 has been subtracted with the first given number, then again 2 has been added with the (subtracted) obtained number.
So, the right answer will be 25.
(2)
Shubhendu Pathak said:
10 years ago
Suppose that it is 2, 1, (1/2), (1/4).
Than we can easily understand by doing this in this way.
Second number multiplied from first number and then get the next number.
Like: 1/2 * 1/4 = 1/8 solved.
Than we can easily understand by doing this in this way.
Second number multiplied from first number and then get the next number.
Like: 1/2 * 1/4 = 1/8 solved.
Trinadh.K said:
1 decade ago
@Lisa Price:
1. 18, 81, 27, 36, 63, 45, 54, 45....
2. 1/64, 1/32, 1/16, 1/8, 1/4, 1/2, 1, 2, 4... (you just multiply with 2).
3. 36, 37, 39, 42, 46, 51, 57, 64.. (+1 +2 +3 +4 +5 +6 +7).
1. 18, 81, 27, 36, 63, 45, 54, 45....
2. 1/64, 1/32, 1/16, 1/8, 1/4, 1/2, 1, 2, 4... (you just multiply with 2).
3. 36, 37, 39, 42, 46, 51, 57, 64.. (+1 +2 +3 +4 +5 +6 +7).
Bhavana said:
8 years ago
Let the given series is A, B, C, D. If we divide D/C OR C/B OR B/A (in the order of the series, we get 1/2).
That shows A * 1/2 =B AND B * 1/2 = C.
SO,THE NEXT TERM IS D*1/2 = 1/4*1/2 = 1/8.
That shows A * 1/2 =B AND B * 1/2 = C.
SO,THE NEXT TERM IS D*1/2 = 1/4*1/2 = 1/8.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers