There were P people in a room when a meeting started. Q people left the room during the first hour, while R people entered the room during the same time. What expression gives the number of people in the room after the first hour as a percentage of the number of people in the room who have been there since the meeting started?  Choices.
A) (P−Q)/(P−Q+R)
B) 100 x (P−Q+R)/(P−Q)
C) (P+R)/(P−Q)
D) 100 x (P−Q)/(P−Q+R)
E) 100 x (P+R)/(P−Q)
Explanatory Answers   The meeting started with P people. Q left the room during the first hour.   So, (P - Q) people have been in the room since the meeting started.   This expression is obviously the denominator of the expression.   To start with there were P people, Q of whom left the room and another R joined the group.   So, the number of people in the room after the first hour = P - Q + R.   This expression is the numerator of the expression.   Required expression = 100 x (P - Q + R)/(P - Q)   Answer 100 x (P−Q+R)/(P−Q)
<result>B</result>
There were P people in a room when a meeting started. Q people left the room during the first hour, while R people entered the room during the same time. What expression gives the number of people in the room after the first hour as a percentage of the number of people in the room who have been there since the meeting started?