Advertisements
Advertisements
प्रश्न
Which term of the A.P. 84, 80, 76, ... is 248?
उत्तर
In the given problem, we are given an A.P and the value of one of its term. We need to find which term it is (n)
So here we will find the value of n using the formula, `a_n = a + (n - 1)d`
Here, A.P is 84, 80, 76
`a_n = 0`
a = 84
Now
Common difference (d) = `a_1 - a`
= 80 - 84
= -4
Thus using the above-mentioned formula
`a_n = a + (n -1)d`
0 = 84 + (n -1)(-4)
0 = 84 - 4n + 4
4n = 88
On further simplifying, we get,
`n = 88/4`
n = 22
Thus n = 22
Therefore 84 is the 22nd term of the given A.P
APPEARS IN
संबंधित प्रश्न
Find the 31st term of an A.P. whose 11th term is 38 and the 16th term is 73.
Find the 12th term from the end of the following arithmetic progressions:
3, 8, 13, ..., 253
A man arranges to pay off a debt of Rs 3600 by 40 annual instalments which form an arithmetic series. When 30 of the instalments are paid, he dies leaving one-third of all debt unpaid, finds the value of the first instalment.
Show that each of the progressions given below is an AP. Find the first term, common difference and next term of each.
(iv) 2, 8, 18, 32,..........
The common difference of the AP `1/p, (1-p)/p, (1-2p)/p,...` is ______.
The sum of first n terms of an AP is 3n2 + 4n. Find the 25th term of this AP ?
If 7 times the 7th term of an AP is equal to 11 times its 11th term, then its 18th term will be ______.
The (n - 1)th term of an A.P. is given by 7, 12, 17, 22,… is ______.
For the AP: –3, –7, –11, ..., can we find directly a30 – a20 without actually finding a30 and a20? Give reasons for your answer.
Which term of the AP: 21, 42, 63, 84,... is 210?
