Advertisements
Advertisements
प्रश्न
The Sum of first five multiples of 3 is ______.
विकल्प
45
55
15
75
Advertisements
उत्तर
The Sum of first five multiples of 3 is 45.
Explanation:-
The given sequence is 3, 6, 9,...
Here,
a = 3
d = 3
n = 5
Therefore,
`"S"_n = n/2 (2a + (n - 1) d)`
`"S"_5 = 5/2 (2a + (5 - 1) d)`
= `5/2 (2(3) + 4(3))`
= `5/2 (6 + 12)`
= `5/2 (18)`
= 5 × 9
= 45
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]
Check whether -150 is a term of the A.P. 11, 8, 5, 2, ....
Find the sum of the following APs.
−37, −33, −29, …, to 12 terms.
Find the sum given below:
`7 + 10 1/2 + 14 + ... + 84`
Show that a1, a2,..., an... form an AP where an is defined as below:
an = 9 − 5n
Also, find the sum of the first 15 terms.
If the ratio of the sum of the first n terms of two A.Ps is (7n + 1) : (4n + 27), then find the ratio of their 9th terms.
Find the sum of the following arithmetic progressions
`(x - y)^2,(x^2 + y^2), (x + y)^2,.... to n term`
Find the sum of the first 40 positive integers divisible by 3
Find the sum of all odd natural numbers less than 50.
The sum of n natural numbers is 5n2 + 4n. Find its 8th term.
How many numbers are there between 101 and 999, which are divisible by both 2 and 5?
Find the value of x for which the numbers (5x + 2), (4x - 1) and (x + 2) are in AP.
Show that `(a-b)^2 , (a^2 + b^2 ) and ( a^2+ b^2) ` are in AP.
Divide 24 in three parts such that they are in AP and their product is 440.
Draw a triangle PQR in which QR = 6 cm, PQ = 5 cm and times the corresponding sides of ΔPQR?
Find the first term and common difference for the A.P.
0.6, 0.9, 1.2,1.5,...
Find the first term and common difference for the A.P.
127, 135, 143, 151,...
In an A.P. sum of three consecutive terms is 27 and their product is 504, find the terms.
(Assume that three consecutive terms in A.P. are a – d, a, a + d).
The A.P. in which 4th term is –15 and 9th term is –30. Find the sum of the first 10 numbers.
The first and the last terms of an A.P. are 8 and 350 respectively. If its common difference is 9, how many terms are there and what is their sum?
The 9th term of an A.P. is equal to 6 times its second term. If its 5th term is 22, find the A.P.
The first and last terms of an A.P. are 1 and 11. If the sum of its terms is 36, then the number of terms will be
If the sum of first n even natural numbers is equal to k times the sum of first n odd natural numbers, then k =
If the first term of an A.P. is a and nth term is b, then its common difference is
The sum of n terms of two A.P.'s are in the ratio 5n + 9 : 9n + 6. Then, the ratio of their 18th term is
The first three terms of an A.P. respectively are 3y − 1, 3y + 5 and 5y + 1. Then, y equals
Mrs. Gupta repays her total loan of Rs. 1,18,000 by paying installments every month. If the installments for the first month is Rs. 1,000 and it increases by Rs. 100 every month, What amount will she pays as the 30th installments of loan? What amount of loan she still has to pay after the 30th installment?
Q.10
Q.12
If the second term and the fourth term of an A.P. are 12 and 20 respectively, then find the sum of first 25 terms:
Write the formula of the sum of first n terms for an A.P.
Find the sum of numbers between 1 to 140, divisible by 4
If the nth term of an AP is (2n +1), then the sum of its first three terms is ______.
In an A.P., if Sn = 3n2 + 5n and ak = 164, find the value of k.
Find the value of a25 – a15 for the AP: 6, 9, 12, 15, ………..
Find the sum of all even numbers from 1 to 250.
Find the sum of first 16 terms of the A.P. whose nth term is given by an = 5n – 3.
The 5th term and the 9th term of an Arithmetic Progression are 4 and – 12 respectively.
Find:
- the first term
- common difference
- sum of 16 terms of the AP.
