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Calculate conditional probability


Pedro observed what customers ordered at his ice cream shop and found the following probabilities:
P(vanilla)=0.3P(sundae)=0.2P(vanilla and sundae)=0.15
Find the probability that a customer ordered vanilla ice cream given they ordered a sundae.
P(vanilla | sundae)=
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3/5
  • a simplified improper fraction, like 7/4
  • a mixed number, like 1 3/4
  • an exact decimal, like 0.75
  • a multiple of pi, like 12 pi or 2/3 pi