Answer:
R = 6S/T
Step-by-step explanation:
R ∝ S/ T
》R = kS/ T
》k = RT/ S
If R = 8 when S = 4 and T = 3
then, k = (8 × 3)/ 4
k = 6
∴ R = (6 × S)/ T
Hello,

You have just to read the arrows un reversed order:
in f we find (-1,-3) so in f^{-1} we find (-1,-3)^{-1}=(-3,-1)
1000 tickets because you would divide 20000 divided by 20 =1,000