7. The 17th term of an AP is 22, and the sum of the first 17 terms is 102. Find

the 1st term and the common difference.

ANSwer: a1=10;d=2

can you please help me understand the working

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- Apr 20th 2013, 09:50 AMBenja303Arthimetic progression help
7. The 17th term of an AP is 22, and the sum of the first 17 terms is 102. Find

the 1st term and the common difference.

ANSwer: a1=10;d=2

can you please help me understand the working - Apr 20th 2013, 10:07 AMPlatoRe: Arthimetic progression help
- Apr 20th 2013, 10:08 AMMarkFLRe: Arthimetic progression help
The nth term is:

The sum of the first n terms is:

Use the second equation to find , then use the first to find . What do you find? - Apr 20th 2013, 10:51 AMBenja303Re: Arthimetic progression help
Ohhh thanks mark. I was doing it was N/2 X the rest. I see . The 2 divides the entire thing. cool. Nice whip by the way.

- Apr 20th 2013, 11:39 AMMarkFLRe: Arthimetic progression help