Question

The sum of odd numbers from 10 to 60 is?

Answer 1

11,13,.....59
a=11
d=2
so 11+(n-1)2=59

n-1 = 48/2
n =25
so sum = 25/2( 11+59)
= 25*35 = 875
thumbs up please

Answer 2

Hey, sup!

We can solve it using AP.

As per the question,

a=11.
d=2.
l=59.

=> T(n)=a+(n-1)d.
=> 59=11+(n-1)2.
=> 59-11=(n-1)2.
=> 48=(n-1)2.
=> 48/2=n-1.
=> n-1=24.
=> n=24+1.
=> n=25.

S(n)=n/2(a+l).
=> S(25)=25/2(11+59).
=> S(25)=25/2 × 70.
=> S(25)= 25×35.
= 875.
So,the sum of odd numbers from 10 to 60 is 875.
Hope it helps.