Asked by Rabinprakash Dahal
There are n arithmetic means between 1 and 31 such that seventh mean:(n-1)th mean =5:9. Find n.
Answers
Answered by
Steve
If there are n means, then the common difference is (31-1)/(n+1) = 30/(n+1)
The kth mean is 1+k*30/n
So, you want
[1+7*30/(n+1)]/[1+(n-1)*30/(n+1)] = 5/9
n = 14
Check:
1,3,5,7,9,11,13,<b>15</b>,17,19,21,23,25,<b>27</b>,29,31
The kth mean is 1+k*30/n
So, you want
[1+7*30/(n+1)]/[1+(n-1)*30/(n+1)] = 5/9
n = 14
Check:
1,3,5,7,9,11,13,<b>15</b>,17,19,21,23,25,<b>27</b>,29,31
There are no AI answers yet. The ability to request AI answers is coming soon!
Submit Your Answer
We prioritize human answers over AI answers.
If you are human, and you can answer this question, please submit your answer.