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July 23, 2014

July 23, 2014

Posted by **Anonymous** on Friday, October 14, 2011 at 8:23am.

- math -
**Reiny**, Friday, October 14, 2011 at 8:33ama+8d=52

a+11d=70

subtract ....

3d = 18

d=6

sub into the 1st equation to find a, then

sum(20) = (2//2)[2a + 19d ]

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