2011, Form B, Question 3 · 4 points
Airline seat upgrades for a frequent flier
Find the chance the first upgrade comes after the third flight, find a binomial probability for 20 flights, and judge whether more than 20 upgrades in 104 flights would be surprising.
This exam had six free-response questions, each scored from 0 to 4. Its Question 6, the Investigative Task, is no longer part of the exam. The current exam has 4 free-response questions in 90 minutes. The skills these questions practice still count.
Not in the current course. Part (a) asks about waiting for a first success, the geometric setting, which the current course no longer includes.
Lessons this question draws on
1 Read the question
The question is College Board's, from the 2011, Form B exam. It starts on page 7 of the PDF. College Board no longer posts this exam, so it opens from the copy of College Board's PDF that the Internet Archive saved on September 15, 2025.
2 Write your answer
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Scoring guidelines (PDF, page 8)
Question, scoring guidelines and Chief Reader report: College Board, from the Internet Archive. The title and summary are ours.