Advertisements
Advertisements
प्रश्न
Find four numbers in AP whose sum is 8 and the sum of whose squares is 216.
Advertisements
उत्तर
(4, 6, 8, 10) or (10, 8, 6, 4)
APPEARS IN
संबंधित प्रश्न
If Sn denotes the sum of first n terms of an A.P., prove that S30 = 3[S20 − S10]
The sum of the first p, q, r terms of an A.P. are a, b, c respectively. Show that `\frac { a }{ p } (q – r) + \frac { b }{ q } (r – p) + \frac { c }{ r } (p – q) = 0`
Find the sum given below:
–5 + (–8) + (–11) + ... + (–230)
Show that the sum of all odd integers between 1 and 1000 which are divisible by 3 is 83667.
In an A.P., if the first term is 22, the common difference is −4 and the sum to n terms is 64, find n.
The 4th term of an AP is zero. Prove that its 25th term is triple its 11th term.
The first and last terms of an AP are a and l respectively. Show that the sum of the nth term from the beginning and the nth term form the end is ( a + l ).
If 18, a, (b - 3) are in AP, then find the value of (2a – b)
How many terms of the AP `20, 19 1/3 , 18 2/3, ...` must be taken so that their sum is 300? Explain the double answer.
Find the first term and common difference for the following A.P.:
5, 1, –3, –7, ...
First term and the common differences of an A.P. are 6 and 3 respectively; find S27.
Solution: First term = a = 6, common difference = d = 3, S27 = ?
Sn = `"n"/2 [square + ("n" - 1)"d"]` - Formula
Sn = `27/2 [12 + (27 - 1)square]`
= `27/2 xx square`
= 27 × 45
S27 = `square`
Choose the correct alternative answer for the following question .
What is the sum of the first 30 natural numbers ?
There are 25 rows of seats in an auditorium. The first row is of 20 seats, the second of 22 seats, the third of 24 seats, and so on. How many chairs are there in the 21st row ?
Q.18
In an A.P. (with usual notations) : given a = 8, an = 62, Sn = 210, find n and d
Solve for x: 1 + 4 + 7 + 10 + ... + x = 287.
If the third term of an A.P. is 1 and 6th term is – 11, find the sum of its first 32 terms.
The sum of first 16 terms of the AP: 10, 6, 2,... is ______.
Kanika was given her pocket money on Jan 1st, 2008. She puts Rs 1 on Day 1, Rs 2 on Day 2, Rs 3 on Day 3, and continued doing so till the end of the month, from this money into her piggy bank. She also spent Rs 204 of her pocket money, and found that at the end of the month she still had Rs 100 with her. How much was her pocket money for the month?
Find the sum of first 25 terms of the A.P. whose nth term is given by an = 5 + 6n. Also, find the ratio of 20th term to 45th term.
