for A.
So first dP/dt= kP
Let p = Poe to power of kt
po= initial population
When t =0 , Po= 102
P=102e to power of kt
From 1935 to 2010= 75 years right?
P= 200,000,000 and t=75 with Initial P=102ekt
200,000,000 = 102e to power of 75k
e to powr of 75k= 200,0000,000 / 102
75k= Loge (200,000,000/ 102)
k= loge(200,000,000/102) / 75
k= 0.193184734 (Press memory into calculator).
Therefore let t =100 (1935-2035)
P=1002 e to power of 100k
and sub in k and you get the answer
Which should be 2.5x10 to power of 10 toads