Answer:
1) 
3) 
4) 
Step-by-step explanation:
1. You can calculate the volume of a cylinder with the following formula:

Where
is the area of the base and
is the height.
2. Therefore, you only need to multiply the area of the base by the height in each option:
1) 
2) 
3) 
4) 
3. Therefore, the options 1), 3) and 4) have equal volumes.
Answer:
13,200 feet
Step-by-step explanation:
Each mile is 5280 feet, times that by 2.5, you get 13,200
Let the number of CD's be x and total cost be y
y=7x-10
*the 7 comes from the price of each individual CD ($7)
*the 10 comes from the discount ($10)