Sequence And Series Question 432
Question: The 100th term of the sequence 1, 2, 2, 3, 3, 3, 4, 4, 4, 4,… is
Options:
12
13
14
15
Show Answer
Answer:
Correct Answer: C
Solution:
[c] $ 1^{st}terms\to 1,2^{nd},terms=2,4^{th},term\to 3, $ $ 7^{st}terms\to 4,11^{th}terms\to 5,…… $ Series is $ 1,2,4,7,11,… $ $ a_{n}=1+\frac{n(n-1)}{2}=\frac{n^{2}-n+2}{2} $ If $ n=14, $ then $ a_{n}=92, $ If $ n=15, $ then $ a_{n}=106. $
BETA
