Samantha and Rashida are planning a trip to Padre Island, Texas, during spring break. Members of the varsity volleyball team, they are looking forward to four days of beach volleyball and parasailing. They will drive Samantha's car and estimate that they will pay the following costs during the trip:

Motel $(4$ nights at $$160)$ $$640$

Food $($each$)165$

Gas in total $114$

Parasailing and equipment rental $($each$)111$

They have reservations at the SeaScape Motel, which charges $$135$ per night for a single, $$160$ per night for a double, and an additional $$15$ per night if a rollaway bed is added to a double room.

Samantha's little sister, Kallie, wants to go along. She isn't into sports but thinks that four days of partying and relaxing on the beach would be a great way to unwind from the rigors of school. She figures that she could ride with Samantha and Rashida and share their room.

Required:

$1.$ Using incremental costs only, what would it cost Kallie to accompany Samantha and Rashida?

$fill in the blank $1$

$2.$ Using the benefits$-$received method, what would it cost Kallie to go on the trip? If required, round your intermediate calculations and final answer to the nearest cent.