Answer:
7 groups, 3 boys and 8 girls
Step-by-step explanation:
Let total number of groups be [tex]x[/tex]
and total hikers in one group be [tex]y[/tex]
if number of girls and boys in every group is same, then
[tex]\frac{21}{x} + \frac{56}{x} = y[/tex]
[tex]\frac{21 + 56}{x} = y\\x*y = 77[/tex] ....(1)
from (1) [tex]x[/tex] will either be 11 or 7
for [tex]x = 11[/tex] the values won't be real.
For [tex]x = 7\\y = \frac{77}{7} \\y = 11[/tex]
so there will be 7 groups with 11 hikers in each groups and every group will have [tex]\frac{21}{7} = 3[/tex] boys and [tex]\frac{56}{7} = 8[/tex] girls
