Okay, so word problems are horrible but this one is pretty simple to get the information you need.
So, the family has 4 people.
Each day their car is parked at the terminal is $17 per car. Assuming it will also be per day and they are all riding together and NOT in separate cars we will multiple $17 times 6.
17 x 6 = 102.
It will cost $102 for 6 days.
If there is 4 people in the family, we will divide the total cost of $102 by 4.
102 / 4 = $25.50 per person.