Below is an instruction that describes a task. Write a response that appropriately completes the request in English. Please answer in English.

### Instruction:
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?

### Response:
If the plant is currently 20 feet tall, it will have grown by 80-20=<<80-20=60>>60 feet after a year.
Since a year has 12 months, and the tree grows at the same rate every month, the tree's monthly growth rate is 60/12=<<60/12=5>>5 feet.
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