The 985 children at a certain school were asked what they prefer to drink with their lunch, and the following responses were obtained.
drink preferences
Percentage soft drinks 457 milk/chocolate milk 257 water 138 tea 44 other 89
The school only serves milk, chocolate milk, or water with lunch. What is the probability that the first student in line for lunch will be served their preferred beverage with their lunch? Round to two decimal places.
A.0.6
B.0.51
C.0.4
D.0.49

Question

The 985 children at a certain school were asked what they prefer to drink with their lunch, and the following responses were obtained. 
drink preferences 
Percentage soft drinks 457 milk/chocolate milk 257 water 138 tea 44 other 89 
The school only serves milk, chocolate milk, or water with lunch. What is the probability that the first student in line for lunch will be served their preferred beverage with their lunch? Round to two decimal places. 
A.0.6	
B.0.51	
C.0.4	
D.0.49

campbell_st · Answer

I'd expect its (257 + 138)/985 =

add the milk and water responses and then divide by the total in the survey. 

hope it helps