we know that
The speed is equal to the distance divided by the time
Let
x---------> the distance Jessica's home to the grocery store
t1-------> the time from Jessica's home to the grocery store
t2------> the time from grocery store to back home
Step 1
<u>Find the distance x</u>
we have

convert to hour



Step 2
<u>Find the time t2</u>

Step 3
<u>Find the average speed for the entire trip</u>
we know that
the average speed is equal

therefore
<u>the answer is</u>
the average speed for the entire trip is 