At its current growth rate, a certain plant will be 80 feet tall after a year. If the plant grows at the same rate every month and is currently 20 feet tall, what's its monthly growth rate in feet?
A step-by-step solution is:
5
If the plant is currently 20 feet tall, it will have grown by 80 - 20 = 60 feet after a year.

Since a year has 12 months, and the tree grows at the same rate every month, the tree grows at 60 / 12 = 5 feet every month.

.

Thus, the answer is 5