The formula s = sqrt 30fd relates the speed S in miles per hour a car was traveling to the length d in feet that the car skidded when brakes were applied. The variable f is the coefficient of friction, which varies depending on the road surface and the condition of the tires. Which set of numbers contains the value of S for f = 0.5 and d = 63?

* sqrt = Square Root

Select one:

a.
whole numbers

b.
irrational numbers

c.
integers

d.
rational numbers