Verbal Reasoning - Series Completion - Discussion
Discussion Forum : Series Completion - Section 1 (Q.No. 4)
Directions to Solve
Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
4.
In the series 2, 6, 18, 54, ...... what will be the 8th term ?
Answer: Option
Explanation:
Clearly, 2 x 3 = 6, 6 x 3 = 18, 18 x 3 = 54,.....
So, the series is a G.P. in which a = 2, r = 3.
Therefore 8th term = ar8-1 = ar7 = 2 x 37 = (2 x 2187) = 4374.
Discussion:
27 comments Page 1 of 3.
Nida said:
6 days ago
Thanks all for explaining it.
Chollangi sankar said:
3 months ago
2 * 3 = 6.
3 * 3 = 18.
18 * 3 = 54.
54 * 3 = 162.
162 * 3 = 486.
486 * 3 = 1458.
1458 * 3 = 4374.
3 * 3 = 18.
18 * 3 = 54.
54 * 3 = 162.
162 * 3 = 486.
486 * 3 = 1458.
1458 * 3 = 4374.
James Antony said:
4 years ago
Thanks @Kanna.
(2)
Nabin bahadur shahi said:
4 years ago
Good method, thanks @Kanna.
(3)
Papai said:
4 years ago
ar^n-1 where n=no of term, a=first elementary.
So,
2*3^7=4374.
So,
2*3^7=4374.
Madalin said:
4 years ago
2 + 2 = 4 + 2 = 6,
6 + 6 = 12 + 6 = 18,
18 + 18 = 36 + 18 = 54,
54 + 54 = 108 + 54 = 162,
162 + 162 = 324 + 162 = 486,
486 + 486 = 972 + 486 = 1458,
1458 + 1458 = 2916 + 1458 = 4374.
2, 6, 18, 54, 162, 486, 1458, 4374. 8th term is 4374.
6 + 6 = 12 + 6 = 18,
18 + 18 = 36 + 18 = 54,
54 + 54 = 108 + 54 = 162,
162 + 162 = 324 + 162 = 486,
486 + 486 = 972 + 486 = 1458,
1458 + 1458 = 2916 + 1458 = 4374.
2, 6, 18, 54, 162, 486, 1458, 4374. 8th term is 4374.
(15)
Amrit hayer said:
9 years ago
The sum of first 3 terms of G.P is 16 and the sum of next 3 terms is 128. Find 1st term, common ratio and sum 20 terms? please solve this.
(1)
Vaishnavi said:
9 years ago
Yes, using formula is also the correct method.
Nigerian boy said:
10 years ago
@Sameer.
From the formula T8 = ar (power N-1).
N stands for Number of terms you are looking for so all you need do is know that you have to subtract 1 from the number of terms.
Eg. 1. When the number of terms in question is 9 then the formula becomes T9 = ar9-1.
2. When it is 5 the formula becomes T5 = ar5-1.
From the formula T8 = ar (power N-1).
N stands for Number of terms you are looking for so all you need do is know that you have to subtract 1 from the number of terms.
Eg. 1. When the number of terms in question is 9 then the formula becomes T9 = ar9-1.
2. When it is 5 the formula becomes T5 = ar5-1.
(1)
Sameer said:
10 years ago
Why ^7 instead ^8 because there find out 8th place?
(1)
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers