Final answer:
a) It would take Emily approximately 11.11 minutes to ride 4 miles. b) Emily's unit rate is 21.6 miles per hour.
Step-by-step explanation:
a) To find how long it would take Emily to ride 4 miles, we can use the concept of unit rate. The unit rate is the amount of a quantity per one unit of another quantity. In this case, the unit rate is the number of miles per minute that Emily can ride her scooter. We can find the unit rate by dividing the total distance by the total time. So, the unit rate is 18 miles / 50 minutes = 0.36 miles per minute. To find how long it would take Emily to ride 4 miles, we can set up a proportion:
0.36 miles / 1 minute = 4 miles / x minutes
Cross multiplying, we get 0.36x = 4, and dividing both sides by 0.36 gives us x ≈ 11.11 minutes. So, it would take Emily approximately 11.11 minutes to ride 4 miles.
b) To find Emily's unit rate in miles per hour, we need to convert the unit rate from miles per minute to miles per hour. There are 60 minutes in an hour, so we can multiply the unit rate by 60 to get the unit rate in miles per hour. The unit rate in miles per hour is 0.36 miles/minute * 60 minutes/hour = 21.6 miles/hour. Therefore, Emily's unit rate is 21.6 miles per hour.