To determine which set of statements is true, let's analyze the given expression and its meaning.
Last Friday, the number of people who watched the movie was \( n \). This Friday, the number of people who watched the same movie is represented by \( 0.72n \).
Let's break this down:
- \( 0.72n \) indicates that the current number of viewers is 72% of \( n \). This can also be interpreted as a decrease in the number of viewers from last Friday since \( 0.72 \) is less than \( 1 \).
To find the percentage decrease:
- The decrease in viewers is \( n - 0.72n \), which simplifies to \( 0.28n \).
- This means there is a decrease of \( 0.28n \), which corresponds to a percentage decrease of \( 28% \).
Now let's analyze each option:
A. The number of people who watched the movie at the theater increased by 28%. An equivalent expression that represents this situation is \( n + 0.28n \).
(This statement is false; it indicates an increase rather than a decrease.)
B. The number of people who watched the movie at the theater decreased by 72%. An equivalent expression that represents this situation is \( n − 0.72n \).
(This statement is false; the decrease is 28%, not 72%.)
C. The number of people who watched the movie at the theater increased by 72%. An equivalent expression that represents this situation is \( n + 0.72n \).
(This statement is false; it indicates an increase rather than a decrease.)
D. The number of people who watched the movie at the theater decreased by 28%. An equivalent expression that represents this situation is \( n − 0.28n \).
(This statement is true; there is indeed a decrease of 28%.)
Therefore, the correct answer is D: The number of people who watched the movie at the theater decreased by 28%. An equivalent expression that represents this situation is \( n − 0.28n \).