The table below shows the number of color pages a printer prints out over a period of time. Printed Pages in Color
Time (min), x
2
6
8
18
Number of pages, y
3
9
12
27

What is the constant of variation?
Two-thirds
Three-halves
2
3
Earnings
(in dollars)
140
170
200
230

Which describes whether the relationship between the earnings and the number of hours represents a direct variation?
He earns 20 more than 10 times the number of hours he works each week, so the earnings vary directly with the hours.
The earnings increase by 30 for every increase of 3 hours, so the earnings vary directly with the hours.
The ratios of earnings to hours are not the same each week, so the earnings do not vary directly with the hours.
The earnings increase at a steady rate, so the earnings do not vary directly with the hours.