Question

A car moves with the speed of 40 kilometre per hour for 15 minute and then pay the speed of 60 kilometre per hour for next 15 minutes find the total distance covered by the car in these 30 minutes

Answer 1

$(2v1v2) \div (v1 + v2) \\ (2 \times 40 \times 60) \div (100) = 48km \: averge \: velocity \\ (48 \times 1000) \div (60) = (distnce \div time) \\ 800 = (d \div 30) \\ d = 24000mts = 24km$