The 9th And 22nd Term Of An A.P Are 29 And 55 Respectively. Find The Sum Of It's First 60 Terms

Answer 1

T(9)=29.............9th term
T(22)=55............22nd term
If the AP is T(n)=T(n-1)+d, then
d=(T(22)-T(9))/(22-9)=26/13=2

T(1)=T(9)-(9-1)d = 13
and therefore
T(n)=11+2n
T(1)=13
T(60)=11+120=131
To find the sum of the 1st to the 60th term, we use Little Gauss's method:
T(1)+T(2)+....T(30)
T(60)+T(59)+...T(31)
-----------------------(add)
T(1)+T(60) + T(2)+T(59) + ...(30 times)
=30(13+131)=4320

Answer 2

Is the answer correct because my teacher did not teach me like this. Please answer me

Answer 3

That method is soo incorrect for solving sum on an AP
You didn't even find the first term and common difference

Answer 4

i'm in doubt of it correctness
can u make the answer more simplified? it a bit mesmerising.

Answer 5

The method is so incorrect I don't know how you got your answers

Answer 6

That's nice and correct,gud!!!!!

Answer 7

Correct that's nice,gud!!!!!!!!!

Answer 8

Answer

Answer 9

Nearest

Answer 10

incorrect

Answer 11

your answer is correct, because i am a mathematician

Answer 12

You are out of point