Exponential Growth/Decay?

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A bacteria colony grows at the rate of 15%/h. In how many hours will the colony double in size?

2007-01-17 12:05:09 · 2 answers · asked by untilyoucamealong04 3 in Science & Mathematics ➔ Mathematics

About 5 hours.

2 = (1.15)^t
log 2 = t(log 1.15)
log 2 / log 1.15 = t

you could also use natural logs:
2 = e^.15t
ln 2 = .15t
t = 4.6 hours

2007-01-17 12:32:38 · answer #1 · answered by davidosterberg1 6 · 0⤊ 0⤋

100% / 15% = 6 2/3 hours.

2007-01-17 20:30:11 · answer #2 · answered by Master of All He Surveys 2 · 0⤊ 0⤋