Step 1 :Let's denote the distances to your friend's house, the store, and the school as \(A=476\) m, \(B=680\) m, and \(C=794\) m respectively.
Step 2 :The time it takes to walk to each of these places is \(15\) minutes, \(45\) minutes, and \(25\) minutes respectively.
Step 3 :We first convert these distances from meters to kilometers, and the time from minutes to hours. So, \(A=0.476\) km, \(B=0.68\) km, \(C=0.794\) km, and the times are \(0.25\) hours, \(0.75\) hours, and \(0.4166666666666667\) hours respectively.
Step 4 :The total distance walked is the sum of the distances to each place, which is \(1.9500000000000002\) km.
Step 5 :The total time spent walking is the sum of the time it takes to walk to each place, which is \(1.4166666666666667\) hours.
Step 6 :The average speed is calculated by dividing the total distance by the total time. So, the average speed is approximately \(1.3764705882352941\) km/hr.
Step 7 :Final Answer: The average speed is approximately \(\boxed{1.38 \mathrm{~km/hr}}\).