Brett took elevator a from the 6th floor to the lobby, the 0 floor. his nonstop tip took 9 seconds.
bragg took elevator b from the 3rd floor to the pool on the 11th floor. bragg nonstop trip took 16 seconds.
sarah took elevator c from the 1st floor to the 10th floor. her nonstop trip took 12 seconds.
which elevator is the fastest?
settle this with tables, graphs, and equations.

range is infinite on both x and y axis positive and negative

step-by-step explanation:

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