Question

Yesterday there were 425 guest called for room service, 255 did not call for room service. What percentage of the guest call for room service.

Answer 1

Let:

x = Guests who called for room service

y = Guests who did not call for room service

N = Total guests

so:

$\begin{gathered} N=x+y \\ where\colon \\ N=425 \\ y=255 \\ 425=x+255 \\ x=425-255=170 \end{gathered}$

Let:

r = percentage of the guests call for room service.​

$\begin{gathered} N\cdot r=x \\ solve_{\text{ }}for_{\text{ }}r\colon \\ r=\frac{x}{N} \\ r=\frac{170}{425} \\ r=0.4 \end{gathered}$

Answer:

40% of the guests called for room service