Answer:
12.5 units or 12 1/2 units
Explanation:
From the question, it uses 7.5 units in 3 hours.
In one hour it will use; 7.5/3 = 2.5 units
If 2.5 units is used in 1 hour
In 5 hours; 5 × 2.5 units will be used. This gives us 12.5 units or 12 1/2 units.