Solution for a logic problem

 1) USP-SP - After n days of vacation, a student observes that:

a) it rained 7 times, either in the morning or in the afternoon;

b) when it rains in the morning, it doesn't rain in the afternoon;

c) there have been 5 afternoons without rain;

d) there were 6 mornings without rain.

We can therefore say that n is equal to:

a)7

b)8

*c)9

d)10

e)11

The solution is beggining with the seven days represented by the circles.

Each less symbol meaning that didn't rain, but the way it is we only gonna have 2 days of rain, so this way we see that we gonna risk one day that didn't rain morning and evening and replce in the end for two days that would be rain in the morning for one and rain in the evening for the other.

And we cont again the days that rained, but isn't 7 days, so we gonna repeat the operation agian, 

that is risk one day that wasn't rain in the morning and evening and replace for two days that was rain in the morning and rain in the evening.

And we gonna count again until we reach the result tha tis is seven days of rain.

First to solve that peoblem we have to see what is the group fir the progbelm if are the days or if are the turns of days or if is rain and not rain, and to see groups we have to see what is staunq, morning and evening are the same day but when rain in the morning dioesn't rain in teh evening. We have to see that they are attached to each other others groups that I tried before.

The origin.

Rute Bezerra de Menezes Gondim