Question 37090
You can solve this by trial-and-error.
If Phyllis has 1 sister, then she would have 2 brothers. One of those brothers has to be Phil. So if that were so, Phil would have 1 brother and 2 sisters, which doesn't work. (if you get confused draw stick figures on paper resembling boys and girls).
If Phyllis has 2 sisters, then she would have 4 brothers. One of those brothers is Phil. So Phil would have 3 brothers and 3 sisters. This works.
There are 4 boys and 3 girls in the family.
(I hope you understood that)

-weeping