Answer:
1. They consist primarily of variables.
2. They are often called formulas.
4. They often describe real-world relationships.
Answer:
x = 30 I'm sure hope this helps
Please see pic for answer and work
Writing and solving an equation of ratios would seem to be the best way to go.
0.045 sec 3 sec
------------- = ------------
1 image x
Then 0.045x = 3, and x = 66 2/3 images, best rounded down to 66 images.