Chapter 6 - Section 6.8 - Exponential Growth and Decay Models; Newton's Law: Logistic Growth and Decay Models - 6.8 Assess Your Understanding - Page 486: 5

See below.

a) $N(t)=N_0e^{kt}$ b) We know that $1800=1000e^{k\cdot1}\\1.8=e^k\\k=\ln1.8\approx0.5877866649$ Thus $N(3)=1000e^{0.5877866649\cdot3}=5832$ c) Our equation is: $10000=1000e^{0.5877866649\cdot t}\\10=e^{0.5877866649\cdot t}\\\ln{10}=0.5877866649\cdot t\\t=\frac{\ln{10}}{0.5877866649}\approx3.92$