Answers

2016-02-26T19:24:48+05:30
The answer of this is 2564........
1 5 1
2016-02-26T19:42:57+05:30
Its a A.P with ' a_{1} ' as 70 and 'd' as 1 and 'l(last term)' as 100

Using the formula :-

  a_{n} = a + (n-1)d

We can find 'n' as

100 = 70 + (n-1)*1
(n-1) = 100 - 70

n = 30 -1 = 29

Thus now we can use the formula, to find the sum...

 S_{n} =  \frac{n}{2}( a_{1}+l )
 S_{n} =  \frac{29}{2}(70+l00 )
Which simplifies to ...
 S_{n} = 2465

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