Jodi and Vance are researching on a deserted island and have to stay on the island for a certain number of weeks to carry out their research. On their first expedition, they stayed for three weeks on the island. They spent two weeks more on the second expedition than they spent on their first expedition. They spent twice as many weeks on their last expedition as they spent on their second expedition. Calculate the total number of days they spent on the island on all the trips. Let's be accurate as possible.
If they spent two more weeks on their second research expedition than they spent on the first week, they spent 2 + 3 = 5 weeks on the island. In the two expeditions, they stayed on the island for a total of 5 + 3 = 8 weeks. On their third expedition, they spent twice as many weeks as they spent on the second week on the island, which is 2 * 5 = 10 weeks. In all three expeditions, they stayed on the island for 10 + 8 = 18 weeks. Since a week has seven days, they spent 18 * 7 = 126 days on the island.
The answer: 126.