Question

what is the sum of 1+3+5+.......+299=?​

Answer 1

$\bf \: your \: answer \: is \: here \: in \: attachment. \\ hope \: this \: helps.$

Answer 2

since given term is in AP with common difference d= 2 and first term a=1 and tn=299

using formula

tn=a+(n-1)d

299=1+ (n-1)2

298=(n-1)2

149=n-1

n=150

using sum of term of AP

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

sn=150(2+149*2)/2

sn=75(150)

sn=11250