Maya is said to be m years old now. We are asked what will be her age after four years from now so we just have to add 4 years from her age now. The correct expression to calculate her age should be m+4. This cannot be seen among the choices given above.
Answer:
The radius is growing at a rate of
ft per minute.
Step-by-step explanation:
From the information given we know that

And we know as well that .

Since everything is changing with the time we can compute the implicit derivative and we would get that

We are told that we are looking for how fast is the radius growing at the instant when the radius has reached 1 ft, therefore 
And when we solve for 
28 would be the correct answer to that equation