Final answer:
Selma's unit rate in miles per hour for Monday's run is found by dividing the distance (3/4 mile) by the time (2/3 hour), giving a unit rate of 1.125 miles per hour. This calculation uses multiplication by the reciprocal of the divisor and is deemed reasonable when compared to similar situations.
Step-by-step explanation:
To find Selma's unit rate in miles per hour for Monday's run, we need to calculate the number of miles she runs in one hour, based on the facts provided.
Selma ran a loop that is 3/4 of a mile long in 2/3 of an hour. To find the unit rate, we divide the distance (in miles) by the time (in hours).
Step 1: Calculate the unit rate.
Unit Rate (miles per hour) = Distance (miles) / Time (hours)
Unit Rate = (3/4) / (2/3)
To divide by a fraction, we multiply by its reciprocal.
Unit Rate = (3/4) × (3/2)
Unit Rate = (3 × 3) / (4 × 2)
Unit Rate = 9/8
Unit Rate = 1.125 miles per hour
Step 2: Check whether the answer is reasonable.
Picturing a similar situation: if someone travels 10 km in 1/3 of an hour (20 min), they would cover 30 km in one hour. Thus, Selma's rate of 1.125 miles per hour is reasonable considering the speed and time she ran.
The unit rate in miles per hour for Selma's run is 1.125 miles per hour.
According to the question, the unit rate is to be expressed in miles per hour (Option b).