Question

find sum of all odd number between 0 and 50

Answer 1

I think this is the answer

Answer 2

Answer:

a + ( n - 1) d = an

=> 1 + ( n - 1) 2 = 49

=> ( n - 1) 2 = 48

=> ( n - 1) = 24

=> n = 25.

So,

Sn = n/2 × ( a +l)

= 25 /2× ( 1 +49)

= 25 /2 × 50

= 25 ×25

= 62