Friday

August 22, 2014

August 22, 2014

Posted by **azmeerahim** on Saturday, February 9, 2013 at 12:28pm.

- Math -
**Steve**, Saturday, February 9, 2013 at 2:28pma+5d = 265

5/2 (2a+4d) = 1445

(a,d) = (305,-8)

So, we want

n/2 (2a+(n-1)d) < 0

n/2 (2*305 + (n-1)(-8)) < 0

n > 77.25

so, you need 78 terms before the sum is negative

makes sense, since the 39th term is negative, so you need another 39 terms to offset the first 39.

**Related Questions**

maths - 1) The first term of arithmetic progression is -20 and the sum of it's ...

Maths - 1..The first 2 terms of a geometric progression are the same as the ...

AP calculus - The sixth term of an Arithmetic Progression is 23 and the sum of ...

arithmetic - Each term of a progression is determined by adding 0.5 to the ...

algebra 2 - An arithmetic progression has 5 terms that have a sum of 200. The ...

Mathematics - The 25 term of an Arithmetic Progression is 7 1/2 and the sum of ...

AP Calculus - The 9th term of an arithmetic progression is 4+5p and the sum of ...

arithmetic - 1. The first and last term of an A.P are, a and l respectively, ...

maths - the sum of the 4th and 6th terms of an A.P is 42. the sum of the 3rd and...

arithmetic - 1. The first and last term of an A.P are, a and l respectively, ...