Please help me find the surface area

The graph represents the gallons of water in a water tank with respect to the number of hours since it was completely filled

An initial investment of $100 is now valued at $150. the annual interest rate is 5%, compounded continuously. the equation 100e0.05t = 150 represents the situation, where t is the number of years the money has been invested. about how long has the money been invested? use your calculator and round to the nearest whole number. years

How do you determine whether a relationship represented as as graph is linear or nonlinear