Answer:
Part A) The rate is 
Part B) In 1 year the tree grows 3 feet
Step-by-step explanation:
Part A) write the rate at which this tree grows as a fractions
we know that
To find out the rate at which the tree grows divide 1/4 foot by 1/12 year
so

Part B) how many feet does the tree grow in 1 year?
we know that
The tree grows at rate of 
Simplify

That means ----> The tree grows 3 ft in 1 year
therefore
In 1 year the tree grows 3 feet
B. 55,000,000 from 54,860,000
Experimental probability is doing a test and basing probability on that.
Like if you roll a dice 100 times and 6 comes up 21 times, the
experimental probability is 21%.