HELP ME CHECK MY HW PLS, Will +1!!!

Will thumbs down if calculations are completely off :(

Harry and Garry are twin brothers, and they each own appliance stores. Harry lives in Charleston, South Carolina and Garry lives in Gainesville, Florida. Even though they live far apart, they talk often, and trade hints an grievances about the appliance retail business. Lately, they have been discussing the fact that in tough economy consumers often hold off on the upgrade of an appliance as long as possible, deciding that they will wait to "trade up" when economy turns around or the appliance breaks, whichever comes first. The brothers are discussing the wisdom of instituting short-term rebates in order to make their appliances more attractive to consumers, and to increase their rather dismal recent sales figures. Unbeknownst to each other, both Harry and Garry decide to institute a retail-level rebate on a specific high-end stove. The prices of the stove are $1,000 and $900 in Harry's and Garry's store, respectively. Both Harry and Garry's rebate offers will be advertised in the Sunday paper and will last one the Just Noticeably nor Garry has done the research necessary to discover category in that economic clime (which, for the target market and that product offer consumers a $180 rebate on th 20% ). Both Harry and Garry decided to the rebate period, which is about their stoves. Harry sold 35 stoves during just prior to the rebate offer. Gary same number that he sold the week which is an increase of about 10 more than stoves during the rebate period, the rebate offer. Did the fact that he did not know the accurate Just Noticeable Difference cost Harry any Money ( 3 points)? Yes/No (Circle one). If yes, how much? (Please specify how you get your answer, otherwise no credit will be given.) Did the fact that he did not know the accurate Just Noticeable Difference cost Garry any Money ( 3 points)? Yes/No (Circle one). If yes, how much? (Please specify how you get your answer, otherwise no credit will be