Advertisements
Advertisements
प्रश्न
Find S10 if a = 6 and d = 3
Advertisements
उत्तर
a = 6 and d = 3 ......[Given]
Since Sn = `"n"/2[2"a" + ("n" - 1)"d"]`,
S10 = `10/2[2(6) + (10 - 1)(3)]`
= 5[12 + 9(3)]
= 5(12 + 27)
= 5(39)
= 195
APPEARS IN
संबंधित प्रश्न
How many terms of the A.P. 18, 16, 14, .... be taken so that their sum is zero?
If Sn denotes the sum of first n terms of an A.P., prove that S30 = 3[S20 − S10]
Find the sum of the following arithmetic progressions: 50, 46, 42, ... to 10 terms
How many terms of the A.P. : 24, 21, 18, ................ must be taken so that their sum is 78?
Choose the correct alternative answer for the following question .
If for any A.P. d = 5 then t18 – t13 = ....
The A.P. in which 4th term is –15 and 9th term is –30. Find the sum of the first 10 numbers.
Find out the sum of all natural numbers between 1 and 145 which are divisible by 4.
Find the sum of all 2 - digit natural numbers divisible by 4.
If `4/5` , a, 2 are three consecutive terms of an A.P., then find the value of a.
The sum of first 20 odd natural numbers is
A manufacturer of TV sets produces 600 units in the third year and 700 units in the 7th year. Assuming that the production increases uniformly by a fixed number every year, find:
- the production in the first year.
- the production in the 10th year.
- the total production in 7 years.
Obtain the sum of the first 56 terms of an A.P. whose 18th and 39th terms are 52 and 148 respectively.
The middle most term(s) of the AP: -11, -7, -3,.... 49 is ______.
An AP consists of 37 terms. The sum of the three middle most terms is 225 and the sum of the last three is 429. Find the AP.
Show that the sum of an AP whose first term is a, the second term b and the last term c, is equal to `((a + c)(b + c - 2a))/(2(b - a))`
If 7 times the seventh term of the AP is equal to 5 times the fifth term, then find the value of its 12th term.
Three numbers in A.P. have the sum of 30. What is its middle term?
The sum of A.P. 4, 7, 10, 13, ........ upto 20 terms is ______.
