Question

At a flea market held each weekend, an artist sells handmade earrings. The table below shows the average number of pairs of earrings sold for several prices. Given the pattern in the table, how much should the artist charge to maximize revenue?

Table:
price: $15 $14 $13 $12
pairs: 50 60 70 80

Choices:
F.$5 <--i think is right
G.$7.50
H.$10
I.$15