Question 3
Answer all ten questions and show detailed solutions. Printed time 60 minutes; each question 4 points. Subcriterion allocations are editorial.
John cycles to Jane’s house and back on a flat straight road, a round trip of 32 km. Throughout the journey the wind has constant speed and direction. Outward, it blows directly behind John and its speed is added to his normal bicycle speed; returning, its speed is subtracted. Total travel time is 2 hours, with the return taking twice the outward time. Find the wind speed in km/hour.
John cycles to Jane’s house and back on a flat straight road, a round trip of 32 km. Throughout the journey the wind has constant speed and direction. Outward, it blows directly behind John and its speed is added to his normal bicycle speed; returning, its speed is subtracted. Total travel time is 2 hours, with the return taking twice the outward time. Find the wind speed in km/hour.