Question

Jestion 3: 3. The 8th term of an AP is 25. The sum of its first 15 terms is
310
375
350
377​

Answer 1

Answer: 375

Step-by-step explanation:

Given,

8th term of an AP is 25.

25 = a+(n-1)d

(where, a = first term, n = no. of term, d = common difference)

25=a+(8-1)d

25=a+7d

Now,

sum of first 15 terms is,

$s = \frac{n}{2} |2a + (n - 1)d| \\ = \frac{15}{2} |2a + (15 - 1)d| \\ = \frac{15}{2} (2)({a + 7d}) \\ = 15 \times 25 = 375$

hence the sum of the first 15 terms is 375.

Answer 2

Answer:

The correct answer is 375....

Step-by-step explanation:

I hope it will help you....