Math, asked by divinarosario19, 1 month ago

The eight term of an AP whose first term is 15 and the common difference is - 3 is (a) - 6 (b) o (c) 6 (d) 39​

Answers

Answered by saranyab620
1

Step-by-step explanation:

Let d is common difference of AP

Now first 4 terms are 5, 5+d, 5+2d, 5+3d

and next 4 terms 5+4d, 5+5d, 5+6d, 5+7d

Given that, the sum of its first four terms is half the sum of the next four terms.

i.e.,

5 + 5+d + 5+2d + 5+3d=25+4d + 5+5d + 5+6d + 5+7d

20+6d=2(20+22d)

20+6d=10+11d

d=2

Hence,  the  common  difference  of  the  given  A.P.  is   2

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