(a+b)+(a+3b)+(a+5b)+....+(a+31b)sn= Tlg bantuin yaa

a+b)+(a+3b)+(a+5b)+...+(a+31b),

.b=2b
U1 =(a+b)
Un = (a+31b)

Un = u1 +(n-1) b
(a+31b) = (a+b) +(n-1) 2b
(a+36b) - (a+b) = (n-1) 2b
31b -b = (n-1) 2b
(31b-b) /2b = ( n-1)
30b / 2b = (n-1)
15 = n-1
15+1 =n
16 =n

Sn = n/2 (u1 +un)
= 16/2 ( a+b +a+31b)
= 8 (2a+32b)
= 16a+256b