Question

Select all of the following that are a direct variation.

Songs are 99 cents each to download.
Tickets for rides at the fair are $1 each.
Arcade games are 50 cents or $1.
To go tubing it is $5 to rent the tube and $7 for each hour.

Answer 1

Only these are direct variations:

Songs are 99 cents each to download.
Tickets for rides at the fair are $1 each.

Because, for each of them, the total value will be always the product of the number of items times a constant (the unit price).