Advertisements
Advertisements
प्रश्न
Find S10 if a = 6 and d = 3.
Advertisements
उत्तर
a = 6 and d = 3 ...[Given]
Since `S_n = n/2[2a + (n - 1)d]`,
`S_10 = 10/2[2(6) + (10 - 1)(3)]`
= 5[12 + 9(3)]
= 5(12 + 27)
= 5(39)
= 195
APPEARS IN
संबंधित प्रश्न
The sum of three numbers in A.P. is –3, and their product is 8. Find the numbers
Find the sum of the following APs.
−37, −33, −29, …, to 12 terms.
Find the sum of the following APs.
`1/15, 1/12, 1/10`, ......, to 11 terms.
Find the sum of all even integers between 101 and 999.
Find the sum of all 3-digit natural numbers, which are multiples of 11.
Find the 6th term form the end of the AP 17, 14, 11, ……, (-40).
If 4 times the 4th term of an A.P. is equal to 18 times its 18th term, then find its 22nd 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 ).
How many two-digits numbers are divisible by 3?
If `4/5 `, a, 2 are in AP, find the value of a.
Choose the correct alternative answer for the following question .
What is the sum of the first 30 natural numbers ?
Choose the correct alternative answer for the following question .
15, 10, 5,... In this A.P sum of first 10 terms is...
The first term of an A. P. is 5 and the common difference is 4. Complete the following activity and find the sum of the first 12 terms of the A. P.
a = 5, d = 4, s12 = ?
`s_n = n/2 [ square ]`
`s_12 = 12/2 [10 +square]`
`= 6 × square `
` =square`
What is the sum of first 10 terms of the A. P. 15,10,5,........?
Find the sum \[7 + 10\frac{1}{2} + 14 + . . . + 84\]
Write the common difference of an A.P. whose nth term is an = 3n + 7.
Q.13
For an A.P., if t1 = 1 and tn = 149, then find Sn.
Activitry :- Here t1= 1, tn = 149, Sn = ?
Sn = `n/2 (square + square)`
= `n/2 xx square`
= `square` n, where n = 75
Find the sum:
`(a - b)/(a + b) + (3a - 2b)/(a + b) + (5a - 3b)/(a + b) +` ... to 11 terms
The sum of A.P. 4, 7, 10, 13, ........ upto 20 terms is ______.
