Maple Lane school carpool: rules for the next two weeks (fictional)

School days: Monday to Friday, two weeks, ten days.
Every school day has two runs: a morning run to school and an afternoon run home.

Kids (6):
- Ada Abara, age 10
- Ben Abara, age 6, needs a booster seat
- Cleo Brooks, age 9
- Dev Chen, age 11
- Eli Delgado, age 8
- Fay Ellis, age 5, needs a booster seat

Cars (the Ellis family has no car):
- Abara minivan: 7 kid seats, 2 booster seats installed
- Brooks sedan: 3 kid seats, 1 booster seat installed
- Chen SUV: 5 kid seats, 0 booster seats installed
- Delgado wagon: 4 kid seats, 2 booster seats installed

Who can drive (same every week):
- Abara: every morning; afternoons Monday, Wednesday, Friday
- Brooks: afternoons only, every day
- Chen: mornings Monday, Tuesday, Thursday; afternoons Tuesday and Thursday
- Delgado: every morning and every afternoon

Rules:
1. Every kid rides on every run, except Dev Chen, who has soccer on Wednesday afternoons and does not ride home that day.
2. A run uses one or two cars. Each car on a run is driven by its own family, who must be able to drive that slot.
3. A car never carries more kids than its kid seats.
4. Ben and Fay each ride in a booster seat, so a car carrying either of them needs a free booster seat for each.
5. Fairness: each family with a car drives between 3 and 8 car trips over the two weeks (a run with two cars counts one trip for each family).
6. The Ellis family owes no trips, because they have no car.