Question

without adding find the sum ( 1+3+5+7+9+11+13+15+17)​

Answer 1

HeRe Is Your Ans

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Given :-

Common Difference ( D ) = 2

Number of Terms ( n ) = 9

1st Term ( a ) = 1

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We know That ,

$sum = \frac{n}{2} (2a + (n - 1)d \\ \\ = > \frac{9}{2} (2 \times 1 + ( 9 - 1)2 \\ \\ = > \frac{9}{2} ( 2 + 16) \\ \\ = > \frac{9}{2} (18) \\ \\ = > \frac{162}{2} \\ \\ = > 81$

$\fbox{ans = 81}$

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$<marquee > hope it helps u$