The question in parenthesis is just background I need the st

The question in parenthesis is just background, I need the starred question answered. Thank you!

(Question 1 A single breeding pair of rabbits is introduced to Australia in 1900. Assume (for simplicity) that each pair can produce 4 offspring each year (2 male, 2 female). Also assume, that all births happen in the last hour of the last day each year and the parents die immediately after offspring are born.

a) How many rabbits are there after 10 years?

b) How many rabbits are there after 25 years?

If they have 20 offspring each year,

c) How many rabbits are there after 10 years?

d) How many rabbits are there after 25 years?)

*Question 2 Now, assume that rabbits reach sexual maturity instantly after being born and all can reproduce continuously (generations overlap). If each pair has 4 offspring and both parents die by the end of the year:

a)How many rabbits are there after 10 years?

b)How many rabbits are there after 25 years?

Solution

if the 4 offspring rabbits will reproduce this 4offspring then the below condition will satisfy.

a) for ten years (220+4) rabbits are alive.

b) for 25 years (25*4!)-(25*2!)+4) rabbits are alive.

c)for 10 years (10*20!)-(10*2!)+4) rabbits are alive.

d) for 25 years (25*20!)-(10*2!)+4) rabbits are alive. here (+4) is written taking 1900 also as a count.