Advertisements
Advertisements
Question
Find the 6th term form the end of the AP 17, 14, 11, ……, (-40).
Advertisements
Solution
Here, a = 7 and d = (14-17) = -3, l = (-40) and n = 6
Now, nth term from the end =[l-(n-1)d]
6th term from the end = [(-40)-(6-1) × (-3)]
= [ -40 + (5× 3)]=(-40+15)/-25
Hence, the 6th term from the end is –25.
APPEARS IN
RELATED QUESTIONS
Find the sum of the following APs.
−37, −33, −29, …, to 12 terms.
How many terms of the AP. 9, 17, 25 … must be taken to give a sum of 636?
Determine the A.P. Whose 3rd term is 16 and the 7th term exceeds the 5th term by 12.
If the 8th term of an A.P. is 37 and the 15th term is 15 more than the 12th term, find the A.P. Also, find the sum of first 20 terms of A.P.
Draw a triangle PQR in which QR = 6 cm, PQ = 5 cm and times the corresponding sides of ΔPQR?
Choose the correct alternative answer for the following question.
For an given A.P. a = 3.5, d = 0, n = 101, then tn = ....
Find the A.P. whose fourth term is 9 and the sum of its sixth term and thirteenth term is 40.
The sum of the first 7 terms of an A.P. is 63 and the sum of its next 7 terms is 161. Find the 28th term of this A.P.
There are 25 trees at equal distances of 5 metres in a line with a well, the distance of the well from the nearest tree being 10 metres. A gardener waters all the trees separately starting from the well and he returns to the well after watering each tree to get water for the next. Find the total distance the gardener will cover in order to water all the trees.
Write the sum of first n odd natural numbers.
The nth term of an A.P., the sum of whose n terms is Sn, is
The sum of n terms of two A.P.'s are in the ratio 5n + 9 : 9n + 6. Then, the ratio of their 18th term is
Q.3
Find the sum of natural numbers between 1 to 140, which are divisible by 4.
Activity: Natural numbers between 1 to 140 divisible by 4 are, 4, 8, 12, 16,......, 136
Here d = 4, therefore this sequence is an A.P.
a = 4, d = 4, tn = 136, Sn = ?
tn = a + (n – 1)d
`square` = 4 + (n – 1) × 4
`square` = (n – 1) × 4
n = `square`
Now,
Sn = `"n"/2["a" + "t"_"n"]`
Sn = 17 × `square`
Sn = `square`
Therefore, the sum of natural numbers between 1 to 140, which are divisible by 4 is `square`.
What is the sum of an odd numbers between 1 to 50?
Find the sum:
`4 - 1/n + 4 - 2/n + 4 - 3/n + ...` upto n terms
If Sn denotes the sum of first n terms of an AP, prove that S12 = 3(S8 – S4)
Calculate the sum of 35 terms in an AP, whose fourth term is 16 and ninth term is 31.
An Arithmetic Progression (A.P.) has 3 as its first term. The sum of the first 8 terms is twice the sum of the first 5 terms. Find the common difference of the A.P.
The sum of 40 terms of the A.P. 7 + 10 + 13 + 16 + .......... is ______.
