The average speed of Gaurav during a two-way journey is 15 km/h. If he walked a distance of 20 km every hour while going, then his speed while returning will be:

Explanation

Let: Distance (one way) = 20 km Going speed = 20 km/h Average speed for the round trip = 15 km/h Step 1: Calculate the Time Taken for the Journey Time taken to go: Since Gaurav covers 20 km at a speed of 20 km/h, the time taken for the journey going is: Time going = 2020km/h km = 1 hour ​ Let the speed while returning be x km/h . Time taken to return: Time returning = 20xkm hours ​ Step 2: Set Up the Average Speed Equation The formula for average speed over the round trip is: Average speed = Total distance Total time ​ Since the total distance for the round trip is 40 km, and the average speed is 15 km/h: 15 = 1+4020 ​ x ​ Step 3: Solve for x Multiply both sides by 1 + 20 x : ​ 15 (1 + 20 x ) = 40 ​ 15 + 300 x = 40​ Subtract 15 from both sides: 300 x = 25 ​ Now, solve for x : x = 300 25 = 12 km/h ​ Answer: Gaurav’s speed while returning will be 12 km/h.