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प्रश्न
Find the sum of the odd numbers between 0 and 50.
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उत्तर
The odd numbers between 0 and 50 are
1, 3, 5, 7, 9 ... 49
Therefore, it can be observed that these odd numbers are in an A.P.
a = 1
d = 2
l = 49
l = a + (n – 1) d
49 = 1 + (n – 1)2
48 = 2(n – 1)
n – 1 = 24
n = 25
`S_n = n/2(a + 1)`
`S_25 = 25/2(1 + 49)`
= `25/2 [50]`
= 25 × 25
= 625
Thus, the sum of odd numbers between 0 and 50 is 625.
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