Stanley planted a tree in his backyard. The manager of the plant nursery he purchased it from told Stanley that the tree would double in height every 4 years. If Stanley’s tree started out only 1.5 feet tall, how tall will it be in 20 years? Write an exponential equation of the general form [math]y = ab^t[/math], where [math]a[/math] is the initial value, [math]b[/math] is the base, [math]t[/math] is the time, and [math]y[/math] is the final value. Then use it to solve the problem.
