At first, we have to find how many mg needed for 24 hours
Since she needs 5 mg every 4 hours, then
Let us find how many 4 hours in 24 hours?
Divide 24 by 4 to find that

That means we need 5 mg for 6 groups of 4 hours
The total of mg for 24 hours = 5 x 6 = 30 mg
Now, the medication F is 10 mg/ml
That means 10 mg given with 1 ml
We need to find how many ml for 30 mg, we will use the equal ratios

By using cross multiplication

Divide both sides by 10

The total for the 24 hours should be 3 ml