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September 18, 2014

September 18, 2014

Posted by **sonia** on Tuesday, November 2, 2010 at 10:48am.

- math -
**Reiny**, Tuesday, November 2, 2010 at 1:10pmarithmetic series

a = 200

d = 50

Sum(n) = (n/2)[2a + (n-1)d]

13500 = n/2 [400 + 50(n-1)]

27000 = n(50n + 350)

50n^2 + 350n - 27000 = 0

10n^2 + 7n - 5400 = 0

n = ..... One answer will be + , the other -, reject the -

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