Solution:
The odd numbers between 0 and 50 are 1, 3, 5, 7, 9 … 49.
Therefore, we can see that these odd numbers are in the form of AP.
Hence,
First term, a = 1
Common difference, d = 2
Last term, l = 49
By the formula of last term, we know,
l = a + (n − 1) d
49 = 1 + (n − 1)2
48 = 2(n − 1)
n − 1 = 24
n = 25 = Number of terms
The sum of n terms of an AP is:
Sn = n /2( a + l )
S25 = 25/2 (1 + 49)
= 25(50)/2
= (25)(25)
= 625