Ahas a promotion if you buy 3 shirts you get 25% off the total price of 3 shirts store b has the same shirts on sale with the promotion that if you buy 3 shirts you get the 3 shirt at 50% discount. store c has the same shirts on sale with a 10 % discount which store gives you the best discount

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?