Question

Solve
the following.
If the 18th and 35th term of an A Pare 49 and 131
resepectively then find the sum of the first 52 terms.​

Answer 1

Answer:

18th term=a+17d=49

35th term=a+34d=131

a+17d=49

a+34d=131

-. -. -

------------------------

-17d= -82

d = 82/17

a + 17 × 82/17 = 49

a + 82 = 49

a = 49 - 82 = - 33

sum of 52 terms = n/2[ 2a+ (n-1)d]

= 52/2[2×- 33 +(52-1) 82/17]

= 26 [ - 66 + 51 ×82/17]

= 26 [ - 66 + 246 ]

= 26 × 180

= 4680