PLEASE HELP :/

Richard and Davina ate dinner at a restaurant together. Davina had a coupon for 25% off their meal. They both agree that they should leave a 20% tip on their meal. However, Richard believes they should calculate the tip before taking into account the coupon, and Davina believes they should calculate the tip after taking into account the coupon. If their meal costs $48.80 before using the coupon, by how much will the tip increase if they use Richard's method instead of Davina's method?