Question

A group of friends traveled at a constant rate. They traveled 2/5 of a mile in 1/4 of an hour.Which of the following statements are true about this unit rate? Select all that apply.A divide 2/5 by 1/4 to find the unit rate per hour B The average speed will be less than 1 mile per hour because the group travels less than a fourth of a mile in1/4 of an hour C The group traveled at an average speed of 1 3/5 miles per hour.D The average speed will be greater than 1 mile per hour because the group travels more than a fourth of a mile in1/4 of an hour .E The group traveled at an average speed of 2 1/4 of a miles per hour.

Answer 1

The distance traveled, d = 2/5 miles = 0.4 miles.

The time taken to travel 0.4miles is given as, t = 1/4 hr = 0.25 hr.

Thus, the average speed, s = distance traveled divided by time taken.

i.e.

$\begin{gathered} \text{average speed = }\frac{distance\text{ traveled}}{\text{time taken}}\text{ = }\frac{0.4}{0.25}\text{ } \\ \text{average sp}eed\text{ = 1.6 miles/hr} \end{gathered}$

we can now go through the options and see the correct answers:

option A is correct because unit rate per hour is the same thing as average speed

option B is wrong because average speed is greater than 1mile/hr from our calculation above

option C is wrong because 13/5 gives us 2.6 miles/hr

option D is correct because the average speed is indeed greater than 1

option E is wrong because average speed is 1.6 miles/hr not 2 1/4 miles/hr

Thus, the answers are:

Option A and Option D