Problem
\[ R=\frac{F}{N+F} \] A website uses the formula above to calculate a seller's rating, \( R \), based on the number of favorable reviews, \( F \), and unfavorable reviews, \( N \). Which of the following expresses the number of favorable reviews in terms of the other variables? A) \( F=\frac{R N}{R-1} \) B) \( F=\frac{R N}{1-R} \) C) \( F=\frac{N}{1-R} \) D) \( F=\frac{N}{R-1} \)
Solution
Step 1 ：\( R = \frac{F}{N+F} \)
Step 2 ：\( F = R(N+F) \)
Step 3 ：\( F = \frac{R N}{1-R} \)
