Question

Megan drove from her house to work at an average speed of 45 miles per hour. The drive took her

Answer 1

Answer:

First option: 30 miles per hour

Step-by-step explanation:

For the first scenario, we will convert the minutes into hours first to get all the quantities in same unit

So,

20 minutes = 1/3 hours = 0.33 hours

Now using the speed, distance and time formula

Speed = distance/time

$Speed = \frac{distance}{time}$

$45 = \frac{distance}{\frac{1}{3} }$

$45 = 3 * distance$$\frac{45}{3} = Distance$

So the distance is 15 miles.

For returning through the same route

Time = 30 minutes = 0.5 hour

Distance = 15 miles

So,

$speed = \frac{distance}{time}$

$Speed = \frac{15}{0.5}$

Speed = 30 miles per hour

So first option is correct..

Answer 2

Answer:

30

Step-by-step explanation:

Since the question says that it took her 45 minutes per hour, you can use that to find the distance of the route she took.  

45 miles: 60 minutes  

15 miles: 20 minutes ----------------cross multiply (20x45 and then divide by 60)  

Therefore, if she is going to use the same route in reverse, the distance would be 15 miles.  

Use the formula for speed:  

speed= distance/time  

= 15/0.5 ---------- 0.5 hours is the same as 30 minutes  

= 30