Level 3 4 m
The distance between town A and town B was 100 km. At 0700 Ali left town A and cycled towards town B. Grace left town A and cycled towards town B at 0730. Grace's cycling speed was 2 km/h faster than Ali. At 1100, Grace caught up with Ali. When Grace was 20 km from town B, she stopped to wait for Ali.
How far was Ali from Grace when she stopped to wait for him?