Advertisements
Advertisements
प्रश्न
The sum of 40 terms of the A.P. 7 + 10 + 13 + 16 + .......... is ______.
पर्याय
5240
2620
1310
2680
Advertisements
उत्तर
The sum of 40 terms of the A.P. 7 + 10 + 13 + 16 + .......... is 2620.
Explanation:
For given A.P, a = 7; d = 10 – 7 = 3
We know that
`S_n = n/2 [2a + (n - 1)d]`
∴ `S_40 = 40/2 [2 xx 7 + (40 - 1)3]`
= 20[14 + 117]
= 20 × 131
= 2620
APPEARS IN
संबंधित प्रश्न
Find the sum of first 30 terms of an A.P. whose second term is 2 and seventh term is 22
Find the sum of the following APs:
–37, –33, –29, ... to 12 terms.
In an AP given l = 28, S = 144, and there are total 9 terms. Find a.
Find the sum of the following arithmetic progressions:
`(x - y)^2, (x^2 + y^2), (x + y)^2` ...., to n terms
Find the sum of two middle most terms of the AP `-4/3, -1 (-2)/3, ..., 4 1/3.`
Which term of the AP 21, 18, 15, ... is zero?
Q.16
How many terms of the A.P. 25, 22, 19, … are needed to give the sum 116 ? Also find the last term.
In a ‘Mahila Bachat Gat’, Sharvari invested ₹ 2 on first day, ₹ 4 on second day and ₹ 6 on third day. If she saves like this, then what would be her total savings in the month of February 2010?
If Sn denotes the sum of first n terms of an AP, prove that S12 = 3(S8 – S4)
