Question

Find thesum of all odd numbers from 1 to 150.​

Answer 1

Sn= n/2 (a+l )

= 25/2 (1 + 49)

= 25/2 x 50

= 625

Answer 2

Ans sum of odd numbers 1+3+5......149

An=a+(n-1)d=149=1+(n-1)2

n=74

Sum of odd numbers =n/2(a+L)

=74/2(150)

=5450.