Thursday

December 18, 2014

December 18, 2014

Posted by **Anonymous** on Wednesday, October 12, 2011 at 5:06am.

- arthmetic -
**Reiny**, Wednesday, October 12, 2011 at 9:42am13th term is 27 --- a + 12d = 27

the 7th iterm is 3 times the 2nd term --> a+6d = 3(a+d)

or

a+6d = 3a + 3d

2a = 3d

a = 3d/2

sub into the first equation

3d/2 + 12d = 27

3d+24d=54

d = 2

then a = 3(2)/2 = 3

I will let you finish it for the sum, you did not say how many terms you want to add.

**Answer this Question**

**Related Questions**

math - the first term of an arthmetic progression is 1 and its last term is 28, ...

Arithmetic Progression - In an AP the 6th term is half the 4th term and the 3rd ...

Math - The fifth term of an arithmetic progression is three times the second ...

Math - 1) If the sum of the first n terms of a series is Sn where Sn=2nē-n, (a)...

math - 1) If the sum of the first n terms of a series is Sn where Sn=2nē-n, (a)...

math sequence and series - In an arthmetic sequence, the fourth term is 84 and ...

GP Caluculus - The third term of a geometric progression is 16. The sum of the ...

GP Caluculus - The third term of a geometric progression is 16. The sum of the ...

GP Caluculus - The third term of a geometric progression is 16. The sum of the ...

math - the fourth term of an arithmetic progression is equal to 3 times the ...