Posted by Hannah on .
Most Americans, 67% in fact, say frequent handwashing is the best way to fend off the flu. Despite that, when using public restrooms, women wash their hands only 66% of the time and men wash only 43% of the time. Of the adults using the public restroom at a large grocery chain store, 58% are women. What is the probability that the next person to enter the restroom in this store washes his or her hands? (Enter your answer to two decimal places.)

statistics 
MathMate,
Use a probability tree:
Next person
male: 42% wash his hands: 43%
female: 58% wash her hands 66%
P(wash)=42%*43% + 58%*66%
=0.5634