Hello everyone(adsbygoogle = window.adsbygoogle || []).push({});

New here and doing some random probability questions in prep for the GRE. I found one and I know it is simple, but I am stumped, and there is no answer online. Here it is--any help is much appreciated.

Ralph is considering whether to use an umbrella. Previously, Ralph's friend Laura had used an umbrella 70% of the time. If Laura does not use an umbrella, the probability that Ralph will use an umbrella is .50. If Laura does use an umbrella, the probability that Ralph uses an umbrella is .25.

a) If Ralph uses an umbrella, what is the probability that Laura did not use an umbrella?

b)What is the probability that Ralph will use an umbrella?

Thanks so much in advance.

**Physics Forums - The Fusion of Science and Community**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Probability Question that I can't figure out

Loading...

Similar Threads for Probability Question can't | Date |
---|---|

I Shopping List Game: Probability Question | Dec 10, 2017 |

I A simple question about probability theory | Aug 2, 2017 |

I Tough probability question | Jun 7, 2017 |

I Question: Proposed Solution to Two Envelope Paradox | Apr 21, 2017 |

Probability question that I just can't solve. | Sep 14, 2006 |

**Physics Forums - The Fusion of Science and Community**