In order to find the answer with the information provided, you have to divide the price given for 3 nights by the number of nights to determine the price per night which would be her daily cost:
$298.17/3=$99.39
According to this, the answer is that the daily cost is $99.39.
Take the # in the last week and times it by 3.5 than you should get the next week. ex: if you wanted to find the 9th week you could do 84 times 3.5 8 times