The details of the packages are not posted, however I can tell you how to find the answer.
First determine how many pencils are in each pack.
Then divide the price of the pack by the number of pencils to find out which pack has the least cost per pencil. To put this in equation form:

Whichever pack has the least cost per pencil is the one that is the best priced.
Answer:
look below
Step-by-step explanation:
x - 5 = 7
x = 12
.................
x - 8 = 20
x = 28
.................
x + 2 = -1
x = -3
................
x - 9 = 12
x = 21
...............
x + -6 = -7
x = -1
.................
x - 8 = -3
x = 5
..................
-7 - x = -9
-7 = x - 9
2 = x
Answer:20cm
Step-by-step explanation:
Circumference=20π
Diameter=circumference ➗ π
Diameter=20π ➗ π
Diameter=20
Diameter=20cm
The answer should be the 3rd one