Can you write the time in terms of the distance and the rate?
B
b
Substitute the given speed into the expression that you found in Part A.
A
a
Expression: 2/w+2/2.5w
l Simplified Expression: 7/2.5w
B
b
48 minutes
Practice makes perfect
a
We are given that Grace's walking speed to her friend's house is w and her jogging speed back to her home is 2.5w. The distance between the houses is 2 miles. We will write an expression to represent the total time that she spends going to and coming from her friend's house. To do so, let's first remember the formula for the time.
Time =Distance/SpeedNow we will identify the amount of time in terms of the corresponding speeds and distance.
Distance
Speed
Time=Distance/Speed
2
w
2/w
2
2.5w
2/2.5w
Now that we have the corresponding times, we can add them up to express the amount of time that she spends going to and coming from her friend's house. Let's do it and then simplify with a common denominator!
We will calculate the minutes that Grace spends going to and coming from her friend's house if she walks about 3.5 miles per hour. To do so let's plug w= 3.5 into the expression that we found in Part A.
Since we have found the time that she spends in hours, now we need to convert it to minutes using a conversion factor.
60 Minutes/1 Hour
Let's multiply 0.8 hour by this conversion factor.
