Final answer:
The unit rate in tons per hour is 2.4 tons per hour.
Step-by-step explanation:
To find the unit rate in tons per hour, we need to divide the total amount of dirt moved by the total time taken. In this case, the construction company can move 7 1/2 tons of dirt in 3 1/8 hours. To convert 7 1/2 tons to a mixed number fraction, we can multiply the whole number (7) by the denominator (2) and add the numerator (1) to get 15/2. Therefore, the unit rate in tons per hour is 15/2 ÷ 25/8 = (15/2) × (8/25) = 120/50 = 2.4 tons per hour.