Level 3
At 7 a.m., a black car and a green car left the office and travelled at average speeds in opposite directions round a 25-km route. The black car took 15 minutes to complete each round while the green car took 20 minutes.
Find the speed of the black car.
Find the speed of the green car.
If the 2 cars travelled without any interval of rest, at what time would the 2 cars next meet again at the office?
Level 3
Bus X and Bus Y left the same bus station at uniform speeds in the same direction round a 48-km circular route. Bus X took 45 minutes to complete each round while Bus Y took 30 minutes.
How long would it take Bus Y to meet Bus Y for the first time? Express the answer in mixed number of hours.
How far would Bus X be behind Bus Y after 12 hour?
Level 3
Helen and Jomarie started off from the same place and drove at uniform speeds in the same direction round a 40-km circular racing track. Helen completed each round in 40 minutes. Jomarie took 50 minutes to complete each round.
How far would Jomarie be behind Helen after 1 hour?
How long after they started would it take Helen to meet Jomarie for the first time?
Level 3
A car uses 9 litres of petrol for every 50 km it travels at an average driving speed is 80 km/h. It uses 6 litres of petrol for every 70 km it travels when it average driving speed is 60 km/h. How much petrol will the car consume use for a journey which lasts 12 h if it travels at 80 km/h for 5 h and 60 km/h for the rest of the journey?