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March 28, 2015

March 28, 2015

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.

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