The third term and nineth terms of an A.P. are 4 and -8 respectively. – InterviewSolution

InterviewSolution

1.	The third term and nineth terms of an A.P. are 4 and -8 respectively. Find which term of A.P is equal to 0.
Answer» Let `a` is the first term of `A.P.` and `d` is the common difference of the `A.P.` Then, `a+2d = 4->(1)` `a+8d = -8->(2)` Subtracting (2)-(1), `a+8d-a-2d = -8-4` `d = -2` Therefore, `a+2(-2) = 4 => a = 8` Let `n` th term of this `A.P.` is `0`. `:. 8+(n-1)(-2) = 0` `=> 8-2n+2 = 0` `=>2n = 10` `=> n = 5` `:.5^(th)` term of the `A.P.` will be `0`.

Discussion

No Comment Found

Related InterviewSolutions

Determine k, so that `K^(2)+4k+8, 2k^(2)+3k+6` and `3k^(2)+4k+4` are three consecutive terms of an AP.
Find the 9th term from the ctowards the first term of the A.P. 5,9,13,....,185
A sum of Rs 700 is to be used to give seven cash prizes to students of a school for their overall academic performance. If each prize is Rs 20 less than its preceding prize, find the value of each of the prizes.
A shop keeper buys a number of books for Rs.80. If he had bought 4 more books for the same amount, each book would have cost his Rs.1 less .How many books did he buy?
The third term and nineth terms of an A.P. are 4 and -8 respectively. Find which term of A.P is equal to 0.
If `a_(n)=3-4n`, then show that `a_(1),a_(2),a_(3), …` form an AP. Also, find `S_(20)`.
The first , second and the last terms of an A.P. are `a ,b , c`respectively. Prove that the sum is `((a+c)(b+c-2a))/(2(b-a))`.
Find the `11^(t h)`from the last term (towards the first term) of the AP : `10 , 7, 4, dot dot dot , 62.`
We know that the sum of the interior angles of a triangle is`180^0`. Show that the sums of the interior angles of polygons with `3,4,5,6`sides form an arithmetic progression. Find the sum of the interior angles ofa 21 sided polygon.
Check whether ` 150` is a term of the AP : 11, 8, 5, 2...