Question

karyn proofreads 15 pages in 2 hours for $40. what is her proofreading rate in pages per hour?

Answer 1

15 in 2 hours is 7.5 in an hour (I divided by 2).  And she would only get $20 for that.
(Half of what she gets in 2 hours)
So her rate is $20 per 7.5 pages per hour.