A company started mining tin on 1st January 2019 A model to find the total mass of tin is given by T = 1200 - 3(n - 20)2
where T is the total mass of tin mined in the n years after the start of mining. Calculate the mass of tin that will be mined in 2023.

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional

answer:   y=2x-3

step-by-step explanation:

not sure but it may be b, as i said i'm not sure.