Can someone help me and explain what to do here?

Which of the following system of equation is not equal to the system of equations is not equal to the system of equations shown below

Over the course of the school year, you keep track of how much snow falls on a given day and whether it was a snow day. your data indicates that of twenty-one days with less than three inches of snow, five were snow days, while of the eight days with more than three inches of snow, six were snow days. if all you know about a day is that it is snowing, what is the probability that it will be a snow day?

Annabelle's homework is 75% it took her three hours how long should she estimate it will take her to complete her homework.