Question

find the sum of all even natural number b/w 100 & 1000

Answer 1

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Answer 2

100----------1000
a=100
d=102-100=2
an=1000
finding value of n
1000=100+(n-1)2
900=(n-1)2
900/2=n-1
450=n-1
n=451

Sn=n/2(a +an)
= 451/2(100+1000)
=451/2×1100
=451×550=248050.

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