Sum of First N Natural Numbers

Q.

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

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Q.

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

1. 100

2. 98

3. 105

4. 110

Q. Find the sum to 100 terms of the series:
1 + 4 + 7 + 5 + 13 + 6 ...

1. 7825
2. 8825
3. 9825
4. 10825

Q. Extending the same logic you’ve seen in the video so far, find out the sum of the first 10 natural numbers
(Consider $S_{10}=1+2+3+\dots +10$ to proceed.).

1. 110
2. 55
3. 66
4. 220
   

Q.

Find the sum of first $n$ natural numbers.

1. $\frac{n(2n-1)}{2}$

2. $\frac{n(2n+1)}{2}$

3. $\frac{2n+1}{2}$

4. $\frac{n(n+1)}{2}$

Q.

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

1. 625

2. 675

3. 700

4. 650

Q.

What is the sum of the first 50 natural numbers?

1. 2550

2. 1275

3. 3000

4. 3250

Q. The $4^{th}$ term of an AP is 9 and the $9^{th}$ term of the AP is 34. The sum of the first 10 terms of the AP is ___

Q.

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

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

Q.

The sum of the first 1000 positive integers is ___.

1. 50051

2. 500500

3. 50050

4. 5005