Advertisements
Advertisements
प्रश्न
Find the sum of first 22 terms of an AP in which d = 7 and 22nd term is 149.
Advertisements
उत्तर
d = 7
a22 = 149
S22 = ?
an = a + (n − 1)d
a22 = a + (22 − 1)d
149 = a + 21 × 7
149 = a + 147
a = 2
`S_n = n/2(a+a_n)`
= `22/2(2+149)`
= 11(151)
= 1661
संबंधित प्रश्न
Check whether -150 is a term of the A.P. 11, 8, 5, 2, ....
The sum of three terms of an A.P. is 21 and the product of the first and the third terms exceed the second term by 6, find three terms.
Find the sum to n term of the A.P. 5, 2, −1, −4, −7, ...,
Find the sum of all multiples of 7 lying between 300 and 700.
If the 10th term of an AP is 52 and 17th term is 20 more than its 13th term, find the AP
Is -150 a term of the AP 11, 8, 5, 2, ……?
The 8th term of an AP is zero. Prove that its 38th term is triple its 18th term.
A sum of ₹2800 is to be used to award four prizes. If each prize after the first is ₹200 less than the preceding prize, find the value of each of the prizes
Find the value of x for which the numbers (5x + 2), (4x - 1) and (x + 2) are in AP.
If an denotes the nth term of the AP 2, 7, 12, 17, … find the value of (a30 - a20 ).
Find the sum of the following Aps:
i) 2, 7, 12, 17, ……. to 19 terms .
Find the sum of all multiples of 9 lying between 300 and 700.
If the ratio of sum of the first m and n terms of an AP is m2 : n2, show that the ratio of its mth and nth terms is (2m − 1) : (2n − 1) ?
The A.P. in which 4th term is –15 and 9th term is –30. Find the sum of the first 10 numbers.
If m times the mth term of an A.P. is eqaul to n times nth term then show that the (m + n)th term of the A.P. is zero.
What is the sum of first 10 terms of the A. P. 15,10,5,........?
Find the sum of n terms of the series \[\left( 4 - \frac{1}{n} \right) + \left( 4 - \frac{2}{n} \right) + \left( 4 - \frac{3}{n} \right) + . . . . . . . . . .\]
The first and last term of an A.P. are a and l respectively. If S is the sum of all the terms of the A.P. and the common difference is given by \[\frac{l^2 - a^2}{k - (l + a)}\] , then k =
If the sum of first n even natural numbers is equal to k times the sum of first n odd natural numbers, then k =
If Sn denote the sum of n terms of an A.P. with first term a and common difference dsuch that \[\frac{Sx}{Skx}\] is independent of x, then
The sum of first n odd natural numbers is ______.
Q.1
Find the common difference of an A.P. whose first term is 5 and the sum of first four terms is half the sum of next four terms.
Write the formula of the sum of first n terms for an A.P.
Find the next 4 terms of the sequence `1/6, 1/4, 1/3`. Also find Sn.
The first term of an AP of consecutive integers is p2 + 1. The sum of 2p + 1 terms of this AP is ______.
Find the sum:
`(a - b)/(a + b) + (3a - 2b)/(a + b) + (5a - 3b)/(a + b) +` ... to 11 terms
Yasmeen saves Rs 32 during the first month, Rs 36 in the second month and Rs 40 in the third month. If she continues to save in this manner, in how many months will she save Rs 2000?
The sum of 41 terms of an A.P. with middle term 40 is ______.
k + 2, 2k + 7 and 4k + 12 are the first three terms of an A.P. The first term of this A.P. is ______.
