# Sum of First N Natural Numbers

## Trending Questions

**Q.**

What is the sum of the first 50 natural numbers?

2550

1275

3000

3250

**Q.**

**Question 3 (iii)**

In an AP:

(iii) Given a12=37, d=3, find a and S12.

**Q.**The 16th term of an AP is five times its third term. If its 10th term is 41, then find the sum of its first fifteen terms.

**Q.**

The first term of an A.P is $2$and the common difference is $4$ The sum of its $40$ terms will be

$3200$

$1600$

$200$

$2800$

**Q.**

Find the sum of first 12 natural numbers without using the formula or by adding terms directly.

58

78

48

98

**Q.**

Find the AP whose sum to n terms is 2 n2 + n.

**Q.**

If 9th and 19th terms of an AP are 35 and 75 respectively, then 20th term is -

80

78

81

79

**Q.**The sum of first 50 natural numbers is

- 1275
- 1175
- 51
- none of these

**Q.**

**Question 3 (v)**

In an AP:

(v) Given d = 5, S9=75, find d and a9.

**Q.**The sum of the first 18 natural numbers is

- 171
- 161
- 181
- 188

**Q.**

The sum of the first 1000 positive integers is ___.

50051

500500

50050

5005

**Q.**Which term of the AP : 3, 8, 13, 18, ..., is 78.

**Q.**Find the sum of the first 10 natural numbers.

**Q.**

Find the sum of the first 18 natural numbers.

171

161

191

181

**Q.**In an AP:

(i) Given a=5, d=3, an=50, find n and Sn.

(ii) Given a=7, a13=35, find d and S13.

(iii) Given a12=37, d=3, find a and S12.

(iv) Given a3=15, S10=125, find d and a10.

(v) Given d=5, S9=75, find a and a9.

(vi) Given a=2, d=8, Sn=90, find n and an.

(vii) Given a=8, an=62, Sn=210, find n and d.

(viii) Given an=4, d=2, Sn=−14, find n and a.

(ix) Given a=3, n=8, S=192, find d.

(x) Given l=28, S=144, and there are total 9 terms. Find a.

**Q.**Find the sum of first 20 natural numbers.

- 210
- 230
- 220
- 240

**Q.**what is algebraic sum?

**Q.**

**Question 3 (i)**

In an AP:

(i) Given a = 5, d = 3, an=50, find n and Sn.

**Q.**Assertion : Sum of first 10 terma of the arithmetio progreasion −0.5, −1.0, −1.5, ……… is 31 .

Reason : Sum of n terma of an AP is given aa Sn=n2[2a+(n−1)d] where a is firat term and d common difference.

- (d) Assertion (A) is false but reason (R) is true.
- (c) Asaertion (A) is true but reason (R) is false.

- (b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).

- (a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

**Q.**Assertion : If sum of the first n terma of an AP is given by Sn=3n2−4n. Then ita nth term is an=6n−7.

Reason: nth term of an AP, whose sum to n terma is Sn, is given by an=Sn−Sn1

- (c) Assertion (A) is true but reason (R) is false.

- (a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

- (d) Assertion (A) is false but reason (R) is true.
- (b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).

**Q.**

To find the sum of the first 24 terms of an AP whose nth term is given by an=3+2n, what is the best approach to solve this question?

- Find the first term and the common difference.
- List out the first 24 terms using the expression for n
^{th}term and add them. - Data insufficient - we need the value of “first term” to be given.
- Data insufficient - we need the value of “common difference” to be given.

**Q.**

**Question 11**

If the sum of the first n terms of an AP is 4n−n2, what is the first term (that is S1)? What is the sum of first two terms? What is the second term? Similarly find the 3rd, the 10th and the nth terms.

**Q.**

Find the sum of all odd numbers between 0 and 50.

625

675

700

650

**Q.**

If the sum of the first 14 terms of an AP is 1050 and its first term is 10, find the 20th term.

**Q.**

The first term of an AP is $5,$ the last term is $45$ and the sum is $400.$ Find the number of terms and the common difference.

**Q.**How many three-digit numbers are divisible by 7?

**Q.**The 4th term of an AP is 9 and the 9th term of the AP is 34. The sum of the first 10 terms of the AP is

**Q.**Extending the same logic you’ve seen in the video so far, find out the sum of the first 10 natural numbers

(Consider S10=1+2+3+…+10 to proceed.).

- 110
- 55
- 66
- 220

**Q.**Find the 31st term of an AP whose 11th term is 38 and the 16th term is 73.

**Q.**

Sum of first 10 terms in 2, 4, 6, 8, ... is

100

98

105

110