[X] Privacy Policy + T&C We use cookies to personalise our content and ads, and for traffic analysis. Information about your use of our site is shared with our advertising and analytics providers. You also agree to our T&C.

Last week I travelled from London to Leeds, which is a distance of 174 miles.

I started at 9.15am and completed the journey with an average speed of 40 miles per hour.

On the way back, in the evening, I travelled exactly the same route, starting at 5.15pm. The traffic was light and I completed the journey with an average speed of 60 miles per hour.

What was the overall average speed for round trip?

The answer is not 50 mph.

Time  = Distance ÷ Speed
Speed = Distance ÷ Time

The outward journey took 174 miles ÷ 40 mph = 4.35 hours.

The return journey took 174 miles ÷ 60 mph = 2.9 hours.

So I travelled a total of 2 x 174 = 348 miles. I did this in a total of 4.35 + 2.9 = 7.25 hours.

My overall average speed was therefore 348 miles ÷ 7.25 hours = 48 miles per hour. QED.

Back to the puzzles...

Top 10 Illusions

 Shadow Illusion Level Balance? Same Length Red Lines? Spinning Dancer Purple Nurple