D
working :
y=k/x
when k=2.8
y=2.8/x
sub y=22.4,
22.4=2.8/x
x=2.8/22.4
x=0.125
The critical values of the function are x = 0 and x = 64
The critical values of a function f(x) are the values of x for which f'(x) = 0.
Given,
f(x) =
The derivative is found as follows, applying the quotient rule:
f'(x) =
=
The zeros of the function are the zeros of the numerator, thus:
x - 64 = 0------------->x = 64
The critical values are x = 0 and x = 64
Learn more about critical values here:brainly.com/question/12958088
#SPJ4
1,680 divided by 400 = 4.2
So we know that Xian has done 4.2 laps.
4.2 divided by 14 = 0.3
0.3 x 100 = 30%
Therefore, Xian has finished 30% of the run