SOLUTION: An arithmetic series has first term 1000 and common difference -1.4. calculate the value of the first negative term of the series, and the sum of all the positive terms

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Question 732802: An arithmetic series has first term 1000 and common difference -1.4. calculate the value of the first negative term of the series, and the sum of all the positive terms
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
a= 1000
d= -1.4
1000/1.4 = 714.29
there are 714.29 =ve numbers
add 1.4 you get 715.69
so 716th number will bwe negative
t716 = 1000+(716-1)-1.4
t716 = -1
-1 is the first negative number.
S715 will be the sum
S715 = 715/2[2*1000+714*-1.4]
S715 = 357643