This cache is part of the St. Charles Plane Geoart series.
The cache is not at the posted coordinates. Solve the puzzle below to get the final coordinates.
Aaron and three of his geocaching friends were heading to a Mega event in Las Vegas for five days. Their main goal was to complete the ET Highway, which has close to 2,000 geocaches. As they boarded the plane, Aaron looked around and saw many passengers wearing geocaching related items so he assumed they must be on their way to the Mega event as well. Aaron stopped halfway down the aisle and turned to one of the passengers, who was wearing a geocaching t-shirt and hat and said, “Wow, there must be 200 geocachers on this flight!” The passenger looked up at Aaron and responded by saying, “That is not true. We would need half of half of us plus three fourths of your group and two more to get to that number.” Aaron, confused by the response, continued to his seat near the back of the plane. After thinking about it for a while he pulled out his geocaching notebook from his geocaching briefcase and used his geocaching pen attached to his geocaching lanyard and started doing some math. He soon came up with a possible answer. But seeing that there was no certitude checker to check his work, he was not able to verify the correct answer and just gave up.
Try to help Aaron out by solving this plane ugly math problem. How many geocachers were on the plane before his group boarded? Luckily, there is a certitude checker to check your answer!

You can validate your puzzle solution with
certitude.