Advertisements
Advertisements
प्रश्न
The first and the last terms of an A.P. are 34 and 700 respectively. If the common difference is 18, how many terms are there and what is their sum?
Advertisements
उत्तर
Let there be n terms in this A.P.
First term a = 34
Common difference d = 18
Last term l = 700
`=>` a + (n – 1)d = 700
`=>` 34 + (n – 1) × 18 = 700
`=>` (n – 1) × 18 = 666
`=>` n – 1 = 37
`=>` n = 38
Sum of first n terms = `n/2 [a + l]`
= `38/2 [34 + 700]`
= 19 × 734
= 13946
APPEARS IN
संबंधित प्रश्न
The sum of three numbers in A.P. is –3, and their product is 8. Find the numbers
In an AP given an = 4, d = 2, Sn = −14, find n and a.
If the sum of first m terms of an A.P. is the same as the sum of its first n terms, show that the sum of its first (m + n) terms is zero
In an A.P. the first term is 25, nth term is –17 and the sum of n terms is 132. Find n and the common difference.
If the sum of first m terms of an AP is (2m2 + 3m) then what is its second term?
The fourth term of an A.P. is 11. The sum of the fifth and seventh terms of the A.P. is 34. Find its common difference.
Find the first term and common difference for the A.P.
0.6, 0.9, 1.2,1.5,...
The Sum of first five multiples of 3 is ______.
The sum of first 9 terms of an A.P. is 162. The ratio of its 6th term to its 13th term is 1 : 2. Find the first and 15th term of the A.P.
If the nth term of an AP is (2n + 1), then the sum of its first three terms is ______.
