Question

if the sum of 1st 6th term of an ap is 36 and that of 1st 16th term is 256. find the sum of 1st 10th term​

Answer 1

Answer:

Step-by-step explanation:

given S6= 36

   6/2(2a + (6-1)d) = 36

   2a + 5d = 12------------------->>1

  S16= 256

  16/2( 2a + (16-1)d=256

  2a + 15d = 32---------------------->> 2

 eq 2 - eq 1

 2a + 15d = 32

 -2a - 5d = -12

___________

10d = 20

d = 2

a= 32 - 15(2)

= 32 - 30

= 2

S10= 10/2(2(2) + (10-1)(2))

    = 5(4+ 18)

   = 5(22)

    = 110