Question

S = F/(U + F)

A web-sïte uses the above formula to calculate a seller's ratïng (S), based on the number of favorable re-views (F), and unfavorable re-views (U). Which of the following expresses the number of favorable re-views in terms of the other variables?

A) F = SU/(S - 1)
B) F = SU/(1 - S)
C) F = U/(1 - S)
D) F = U/(S - 1)​

Answer 1

$S = \dfrac{F}{U + F}\\ \\ \Rightarrow S \times (U+F)=F \\ \\ \Rightarrow SU+SF=F\\ \\ \Rightarrow SU=F-FS \\ \\ \Rightarrow F(1-S)=SU\\ \\ \Rightarrow \bold{F=\dfrac{SU}{1-S}}$

Answer 2

Answer:

F = SU/1-S (b)

Hope It Helps!