Option 2: (x-4)^2 + (x-5)^2 = 4
The given circle's center is: (4,5)
And the radius is 4 units.
We are told in the question that the center will remain same only the radius will be changed.
The center is denoted by (h,k) = (4,5) and radius is 2
Standard equation of circle is:
(x-h)^2 + (y-k)^2 = r^2
So the equation of another circle with same center and radius of 2 units will be:
(x-4)^2 + (x-5)^2 = 2^2
(x-4)^2 + (x-5)^2 = 4
Hence option 2 is correct ..
4a. is 3 miles every hour
4b. is 1/3 of an hour per mile