Answer:
7 groups, 3 boys and 8 girls
Explanation:
Let total number of groups be
![x](https://img.qammunity.org/2020/formulas/mathematics/middle-school/k3ozza40nv61jy1offmxaxutrb6y1c3ly5.png)
and total hikers in one group be
![y](https://img.qammunity.org/2020/formulas/mathematics/college/uw0b7dbqmfpakodpw1nh8u5h9nrcutx8vw.png)
if number of girls and boys in every group is same, then
![(21)/(x) + (56)/(x) = y](https://img.qammunity.org/2020/formulas/mathematics/middle-school/1y3bp11ebp0rasrcux45y797h6wt8k4hbp.png)
....(1)
from (1)
will either be 11 or 7
for
the values won't be real.
For
![x = 7\\y = (77)/(7) \\y = 11](https://img.qammunity.org/2020/formulas/mathematics/middle-school/qaqmavwzxt2vzr5lxxk1xof7n6oft0ivpz.png)
so there will be 7 groups with 11 hikers in each groups and every group will have
boys and
girls