Question

(iv) एका अंकगणिती श्रेढीमध्ये पहिले पद 4 असून शेवटचे पद 31 आहे. सर्व पदांची बेरीज 420 आहे;
तर n ची किंमत किती?​

Answer 1

Answer:

12345678910111213223

Answer 2

Given:

एका अंकगणिती श्रेढीमध्ये पहिले पद 4 असून शेवटचे पद 31 आहे. सर्व पदांची बेरीज 420 आहे

For an A.P., the first term is 4 and the last term is 31. The sum of all the terms is 420.

To find:

तर n ची किंमत किती?

What is the value of n?

Solution:

Let

"a" → first term of the A.P. = 4

"l" → last term of the A.P. = 31

"n" → no. of terms in the A.P.

We know the formula of calculating the sum of all terms of an A.P. is as follows:

$\bigstar \boxed{\bold{S_n = \frac{n}{2} [a+l]}}\bigstar$

Now, we have the final equation as:

$420 = \frac{n}{2} [4 + 31]$

$\implies 420 = \frac{n}{2}\times 35$

$\implies n = \frac{420 \times 2 }{35}$

$\implies n = \frac{60 \times 2 }{5}$

$\implies \bold{n = 24}$

Thus, the value of n is → 24.

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