2x is not a way to express this. You could use 2 + x or x +2. But 2x is x multiplied by 2. x + 2 is x plus 2.
There are two scales that may be possible for this scale model; one where it's for every foot and one where it's for every meter.
The for every foot would be better to find out since the scale would be easier to use.
First, you have to divide each sided by 4.2, since you want to find how many meters for each foot.

For every 1 foot used in the model, the actual will be 125 meters.
1 ft = 125 m
8 ft= ___ inches
1 ft= 12 inches
8 ft= 12 x 8 inches
8 ft=96 inches
She has 96 inches, but she needs 100 inches. So she needs 4 more inches of lumber.
Answer:
1:21
Step-by-step explanation:
Easiest trick way to do this is do 26/546 on your calculator (if you got a scientific one) this would simplify this to its lowest fraction which can be converted into a ratio in this case the ratio of teachers to students is 1:21