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Please help, ty!!

 Apr 26, 2018
 #1
avatar+2441 
+3

Part A:

 

Let's condense the information we know. I find this small regrouping step helps me immensely.

  • There are 65 adults
  • There are 15 children
  • 41 out of 65 adults ate popcorn
  • 6 out of 15 children ate popcorn
  • There are 80 people in total

You can even make a quick table, but I think there is not enough information where this is necessary.

 

\(P(\text{Child or Bought Popcorn})=P(\text{Child})+P(\text{Bought Popcorn})-P(\text{Child and Bought Popcorn})\\ P(\text{Child or Bought Popcorn})=\frac{15}{80}+\frac{47}{80}-\frac{6}{80}=\frac{56}{80}=\frac{7}{10}=0.7\)

 

Part B:

 

\(P(\text{Adult or No Popcorn})=P(\text{Adult})+P(\text{No Popcorn})-P(\text{Adult and No Popcorn})\\ P(\text{Adult or No Popcorn})=\frac{65}{80}+\frac{80-(41+6)}{80}-\frac{65-41}{80}\\ P(\text{Adult or No Popcorn})=\frac{65}{80}+\frac{33}{80}-\frac{24}{80}=\frac{74}{80}=0.925 \)

 Apr 26, 2018

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