I think it's D. I will admit that I'm an educated guess.
Answer:
Combined time: 55.316 seconds
The difference in times: 0.856 seconds
Tips:
It is addition and subtraction. A basic calculator should help with any other questions such as this one!
I could be wrong, but I would say it's 18.325
Answer:
To find the area of a square with only the diagonal known,
Square the diagonal and divide by 2:
8^2 = 64
64/2 = 32
The area is 32 cm^2
