Nanyang prelim 2011

Ali and Ben started jogging from Park X to Park Y at the same time. Ali jogged at an average speed of 7.5km/h while Ben jogged at an average speed of 4.5km/h. After jogging for 1.2h, Ali decided to turn back and jog towards Ben. Ali met Ben at point Z which was halfway btw Park X and Park Y. Ali and Ben then continued their jog together towards Park Y at an average speed of 4.5km/ h. What was the distance between park X and park Y.

Age problem

When Kok’s age was twice as Bala’s age, Mike’s age was 30. When Mike’s age was twice Kok’s age, Bala’s age was 21. Given that Mike was the oldest among the three persons, find Bala’s age when Mike was 62 years old. Thanks.

Thanks.