[Question]: Elsa and her sister watch an opera show every year at Central City Opera. Last year, opera seating cost $85 per ticket. This year, it costs $102. What is the percent increase in the cost of each ticket?
[Answer]: The ticket price increase is $102 - $85 = $17. So there is 17 / 85 x 100% = 20% increase of price.
So the answer is 20.

[Question]: Every time Carl earned $0.50 he would go to the corner market and buy a candy bar. Carl's neighbor said he would pay him $0.75 every week for taking out his trash. At the end of four weeks, how many candy bars will Carl be able to buy?
[Answer]: He is paid $0.75 every week for 4 weeks, so Carl made .75 * 4 = $3.00 in 4 weeks. Each candy bar cost $0.50 and he made $3.00 so 3.00 / .50 = 6 candy bars.
So the answer is 6.

[Question]: Jo reads at a steady pace. Her current book has 210 pages. Now, she is at page 90. An hour ago, she was at page 60. For how many hours will she be reading the book?
[Answer]:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
She reads 90 - 60 = 30 pages in an hour. She needs to read 210 - 90 = 120 more pages. For an additional 120 pages, she will need 120 / 30 = 4 hours.
So the answer is 4.