Answer:
For the first question, there is a 39% chance for only boys and a 61% chance for only girls. For the second one it is, about 136 groups.
Explanation:
100: 224 = 61:x → 61/100 = x/224
100x = 13664
x = 136.64 → 136 groups (You can't round up if you don't have enough people)
Hope this helped!