Which of the following expressions show inverse proportionality? y =kx x =ky y=x/k y=k/x

Two values are said to be inversely proportional when the value of one increases, the other decreases. Hence inverse proportionality is expressed in a fraction

y∝

as the value of x increases, the value of y will decrease

This is expressed as an equation using the inverse proportionality constant k

y= k.

or

y=

Hence the fourth option is the correct answer

f(x) has value 150 at x= 0

and 0 at x= 3

so d(f(x))/dt = slope = -150/3 = -50