b(t) = 4(2)^t
b(1) = 4(2)¹ = 4 * 2 = 8
b(2) = 4(2)² = 4 * 4 = 16
b(3) = 4(2)³ = 4 * 8 = 32
b(4) = 4(2)⁴ = 4 *16 = 64
b(5) = 4(2)⁵ = 4 *32 = 128
8 + 16 + 32 + 64 + 128 = 248
248 / 5 = 49.60
248 bacteria in 5 minutes.
49.60 bacteria per minutes
5/248 = 0.020 minutes per bacteria