Question

please answer this question

Answer 1

its sum of all odd numbers till 49
we can use AP or simply use the formula n²
here ,n² =49² =2401

Answer 2

1 + 3 + 5 + 7.....+ 49 = ?

To solve this we can use Arithmetic operations:

A.P. = 1, 3, 5, .....49
a = 1
an = 49
d = 3 - 1 = 2

an = a + (n - 1)d
49 = 1 + (n - 1)2
(n - 1) = 48/2
n = 25

Sn = n/2(2a + (n - 1)d)

= 25/2(2×1 + (25 - 1)2)

= 25/2(2 + 48)

= 25/2(50)

= 25×25

= 625

Therefore,

1 + 3 + 5 +......+ 49 = 625