Hey!
You can make a proportion:

Cross multiply

Divide by 2

<em>5 pounds would cost $10.50</em>
Good luck and hope this helps! :)
Step-by-step explanation:
This is an example of correlation because there is an obvious relationship between the two scenarios.
The answer is -2 because the the next one is -3
Let the length be l, width w and height h, then
Volume = length x width x height
l = 10cm, w + h = 18cm
V(h) = 10(18 - h)h = 180h - h^2
V(h) = 180h - h^2
A GCF is the greatest common factor. It is the largest number that fits into other numbers. A seven cannot fit into a number smaller than itself, that doesn't work. Try to fit 7 into a smaller number like 4, it doesn't work.
Option A is 21 and 3 and Option C is 7 and 1. Those can be eliminated because 7 is larger than 3 and 1.
Option B is 7, 14. 7 Is the largest number that goes into 7 and it goes into 14. So B works.
28 and 7 is Option D. 7 is the largest number that goes into 7 and it goes into 28, so D works.