Mathematical Modeling Practice Test

A savings account earns simple interest according to the equation $A = 1000 + 50t$, where $A$ is the amount in dollars and $t$ is the number of years. How much interest is earned after 5 years?

A plant grows at a constant rate of 2 cm per day. If the plant is initially 5 cm tall, which equation models the height $h$ of the plant after $d$ days?