A colony of fruit flies doubles every 10 mins. If there are 19683 flies now how many were there an hour ago

Question

exponents for when the fruit flies double

Answer 1

The population P(t) obeys the law

 

P(t) = P₀ (2)^t/10,

 

where t is the time in minutes from when the population was P₀.

 

60 minutes ago, P was P₀.  Now it is 19683.

t = 60 minutes

 

19683 = P₀ (2)^60/10 = P₀ (2)⁶

 

P₀ = 19683 / 2⁶ = 308 (to the nearest whole number)

Answer 2

a_n = a₁(r)^n-1

 

19683 = a₁(2)^6-1

19683 = a₁(32)

615.09375 = a₁

 

Not sure how you can have a fraction of a fruit fly.