bantu jawab......,......

waktu pembelahan sebanyak
= 2 jam ÷ 15 menit
= 2×60 menit ÷ 15 menit
= 120 menit ÷ 15 menit
= 8 kali pembelahan

U1 = a = 25
r = 2

S8 = {25 × [(2^8) - 1]} / (2-1)
S8 = [25 × (256 - 1)] / 1
S8 = (25 × 255)
S8 = 6.375