+253 A grey squirrel population was introduced in a certain county of Great Britain 40 years ago. Biologists observe that the population doubles every 8 years, and now the population is 100,000.
+33616 Let the initial size be N0.
After 8 years N = 2*N0.
After 2*8 =16 years N = 2*2*N0 = 4N0.
After 4*8 = 32 years N = 2*4*N0 = 8N0.
After 8*8 = 64 years N = 2*8*N0 = 16N0.
So it seems like the pattern is:
After n*8 years N = 2*n*N0.
When n*8 = 40, we can see that n must be 5 (since 5*8 = 40) and we are told N = 100,000 so:
100000 = 2*5*N0.
N0 = 100000/10 or N0 = 10,000
10 years from now is 50 years from the start, so n*8 = 50, n = 50/8
N = 2*(50/8)*10000 = 125,000
+33616 Let the initial size be N0.
After 8 years N = 2*N0.
After 2*8 =16 years N = 2*2*N0 = 4N0.
After 4*8 = 32 years N = 2*4*N0 = 8N0.
After 8*8 = 64 years N = 2*8*N0 = 16N0.
So it seems like the pattern is:
After n*8 years N = 2*n*N0.
When n*8 = 40, we can see that n must be 5 (since 5*8 = 40) and we are told N = 100,000 so:
100000 = 2*5*N0.
N0 = 100000/10 or N0 = 10,000
10 years from now is 50 years from the start, so n*8 = 50, n = 50/8
N = 2*(50/8)*10000 = 125,000
