There are 4/7 boys, so there are 3/7 girls.
Let the total number of children be x.
4/7x = 8
1/7x = 8 ÷ 4
1/7x = 2
3/7x = 2 x 3
3/7x = 6
There are 6 girls.
25.59- 9.99= 15.60
15.60/ 0.05 = 312
312 minutes this month
I have attached a chart of the given information. Using subtraction from 100 and the other totals, you should be able to figure out the answer. If not, comment and I will send the completed chart