A person runs at an average speed of 20 km/h for 30 minutes and cycles at a speed of 32 km/h for 1 hour 15 minutes. Calculate the average speed (in km/h, rounded off to 1 decimal place).

28.6

Average Speed = \(\frac{Total\; Distance }{Total\; Time }\)

Distance = Speed × Time

Total distance = 20 × \(\frac{30 }{60 }\)  +  32 × \(\frac{75 }{60 }\)

= 10 + 40 = 55 km

Total time =   \(\frac{30 }{60 }\) +   \(\frac{75 }{60 }\) =   \(\frac{105 }{60 }

Average speed =   \(\frac{50 × 60 }{105 }\) = 28.57

= 28.6 km/h