Answer:
325.5 $
Explanation:
series is 3+3.5 +4 +4.5 + .............31 TERMS
THIS IS CLEARLY AN AP (ARITHMETIC PROGRESSION)
FIRST TERM = a = 3
number of terns = n = 31
common difference = d = 0.5
sum of n terms = Sn = ?
formula is Sn = (n/2){ 2a +(n-1)d}
Sn = (31/2){2×3 +(31-1)(0.5)}
Sn = (15.5)(6+30×0.5)
Sn= (15.5)(6+15)
Sn = 15.5×21
Sn = 325.5 $