An arithmetic progression has 10 terms. Sum of the 10 terms is 220. Sum of the odd terms is 100. Find the first term and common difference. pl give me the answer.

Question

maths - Steve Monday, July 17, 2017 at 12:11pm

10/2 (2a+9d) = 220
5/2 (2a+4*2d) = 100
maths - kumar yesterday at 12:10pm

sir,
I get the answer
First term = 18.4 common difference = 4/5
is it correct ?

Answer 1

That's not what I get. Where's your work?

Did you try actually using your results to see whether they produce the desired AP?

Answer 2

sorry.its my mistake.

10/2(2a+9d)=220
5 (2a+9d)=220
(2a+9d)=220/5=44..........[1]
5/2(2a+4x2d)=100
2.5(2a+8d)=100
(2a+8d)=100/2.5=40.......[2]
[1]-[2]=d=4
:. 2a+32=40 a=4

Answer 3

that's better