1.

the 14th term of an ap is twice its 8th term if it is 6th term is minus 8 then find the sum of the first 20 terms​

Answer»

Answer:

Given 14th TERM of ap is twice 8TH term

6th term is -8

sum of FIRST nterms in ap

=n/2(2A+(n-1)d

Step-by-step explanation:

  1. a+13d=2a+14d
  2. =>a=-d
  3. so 6th term is -8
  4. a+5d=-8
  5. 4d=-8
  6. d=-2
  7. a=2
  8. so sum offirst 20 terms
  9. =20/2(2+19(-2))
  10. = -360


Discussion

No Comment Found

Related InterviewSolutions