Question

. A class has 40 students. For flood relief fund each student contributed as many
rupees as the square of his roll number. What is the total collection?​

Answer 1

Step-by-step explanation:

sn =n/2[2a+(n-1)xd S40=40/2 [2x1+(40-1)x1] © S40=40/2(41) © s40= 40 x20.5 40x20.5=820.0

Answer 2

Answer:

The final answer is Rs. 22140. The total collection for the flood relief fund is Rs. 22140.

Step-by-step explanation:

Given that,

Number of students in the class = 40

Each student contributed money equal to the square of their roll number.

Assume the roll numbers of students starts from 1 and end at 40.

Total collection = $1^{2} + 2^{2} +3^{2} +........+39^{2} +40^{2} = \frac{40(40+1)(2*40+1)}{6}$

We can compute the total collection using the following formula:              

$1^{2} + 2^{2} +3^{2} +........+(n-1)^{2} +n^{2} = \frac{n(n+1)(2n+1)}{6}$

Here, in our question n = 40

Substituting n = 40 in the above formula, we get

$1^{2} + 2^{2} +3^{2} +........+39^{2} +40^{2} = \frac{40(40+1)(2*40+1)}{6}$

                                                   $= \frac{40(41)(80+1)}{6}$

                                                   $= \frac{40(41)(81)}{6}$

                                                    $= \frac{132840}{6}$

                                                   $= 22140$

So, $1^{2} + 2^{2} +3^{2} +........+39^{2} +40^{2} = 22140$.

Total collection = Rs. 22140

Therefore, the total collection for the flood relief fund is Rs. 22140.

To know more about the square of a number, visit the below links:

https://brainly.in/question/29854136

https://brainly.in/question/7544373

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