Mathematics for IGCSE & O level - Ratio And Proportion (Section 3 - No. 26)
A journey can be completed in 64 minutes at an average speed of 50 kilometers per hour. How long would the same journey take at an average speed of 40 kilometers per hour?
51.2 minutes
60 minutes
80 minutes
90 minutes
Forklaring
Speed and time are inversely proportional. If the speed decreases to 4/5 of the original speed, then the time will increase to 5/4 of the original time. (5/4) * 64 minutes = 80 minutes.