What is Emma speed in miles per hour?

Question

 Emma walk 1 1/2 miles to school in 2/3 of an hour.

Answer 1

We are given miles and we are given hours;  we just need to compute miles per hour, or miles/hour.

 

   (1 1/2) miles / (2/3) hour

    (3/2) miles / (2/3) hour                 [change mixed number to improper fraction]

     (3/2)*(3/2)  miles/hour             [to divide by fraction, invert and multiply]

       9/4  miles/hour

       2 1/4 miles/hour                    [change improper fraction back to mixed number]

 

Answer 2

We have to remember the relationship between distance, rate and time.

 

d = rt

 

Since we're asked for the speed (rate) per hour, let's first convert the time 2/3 hour to a decimal (0.667 hour).

Distance, d = 1.5 miles

 

So, d=rt

1.5 = 0.667r

 

Divide both sides by 0.667 to isolate the variable r, the rate.

 

1.5/0.667 = r

r = 2.25

Emma's speed is 2.25 miles per hour.

 

Hope this helps.

Answer 3

By dividing miles by hour, we get the unit miles per hour.  Be sure to convert the mixed number into a fraction first.

 

 

(3 / 2  miles) / (2 / 3  hours)

 

 

When we divide by a fraction, we multiply by the reciprocal of the second fraction.

 

(3 / 2  miles) * (3 / 2  hours) =

 

9/4  mile per hour'

 

 

Convert this fraction to a mixed number.

 

(4  / 4) + (4 / 4) + (1 / 4) = 1 + 1 + 1/4

                                       = 2 + 1/4

                                       = 2 1/4

 

 

In decimal form, this is 2.25  miles per hour.

 

 

This means for each hour, Emma walks 2.25 mile.