need help this one question

Tools Keep the Highest 2 / 3 Menyis 5, a decision at the margin Binla is a hard-working college senior one Thursday, she decides to work nonstop until she has answered 250 prtactics problems for her chemistry course, She starts wolka at 9:Do AM and uses a table to keep track of her progress throughout the day. She notices that as she gets s Tips tired, it takes her longer to solve each problem. ss Tips Time Total Problems Answered e for a FREE 7- gage Unlimited 8:00 AM e Unlimited 9:20 AM 100 tbooks 10:00 AM 175 for Free 11:00 AM 225 Noon 250 am more e Feedback Use the table to answer the following questions. The marginal, or additional, gain from Rina's first hour of work, from 8:00 AM to 9:00 AM, is problems. The marginal gain from Rina's third hour of work, from 10:00 AM to 11:00 AM, is problems. Later, the teaching assis