Question

sum of all odd number from 1 to 350​

Answer 1

AP is: 1,3,5,...........,349

a=1

d=3-1

d=2

An=349

An=a+(n-1)d

349=1+(n-1)×2

349-1=2(n-1)

348=2(n-1)

348/2=n-1

174=n-1

174+1=n

n=175

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

S175=175/2[2×1+(175-1)2]

S175=175/2[2+174×2]

S175=175/2[2+348]

S175=175/2×350

S175=175×175

S175=30625

hope this answer will help you.