At one high school, the average amount of time tenth-graders spend watching television each week is the principal introduces a campaign to encourage the students to watch less television. one year later, the principal wants to perform a hypothesis test to determine whether the average amount of time spent watching television per week has decreased.

He ! a group of farmers planned to clean 80 acres of wheat per day to finish the work on schedule. right before the work started, they received a new piece of machinery that them clean 10 more acres per day than originally planned. as a result of increased productivity in the last day before the deadline they only had to clean 30 acres. how many acres of wheat did the group of farmers have to clean?