Answer:
(a). 15
(b). 78
Explanation:
Growth of the population of a fruit fly is modeled by
N(t) =

where t = number of days from the beginning of the experiment.
(a). For t = 0 [Initial population]
N(0) =

=

=

= 15
Initial population of the fruit flies were 15.
(b).Population of the fruit fly colony on 11th day.
N(11) =

=

=

=

=

= 77.82
≈ 78
On 11th day number of fruit flies colony were 78.