The distance between Town Q and Town R was 185 km. At 06 00, Marion left Town Q and cycled towards Town R. Mary left Town Q and cycled towards Town R at 06 40. Mary's cycling speed was 3 km/h faster than Marion. At 9 00, Mary caught up with Marion. When Mary was 17 km from Town R, she stopped to wait for Marion. How far was Marion from Mary when she stopped to wait for him?
Duration in which Mary cycled for before she caught up with Marion
= from 06 40 to 9 00
= 2 h 20 min
= 2 ²⁰₆₀ h
= 2 ¹₃ h

Distance that Mary cycled more than Marion
= 2¹₃ x 3
= ⁷₃ x 3
= 6 km

Marion's cycling speed
= 6 x 3
= 18 km/h

Mary's cycling speed
= 18 + 3
= 21 km/h

Distance that Mary cycled before she stopped to wait for Marion
= 185 - 17
= 168 km

Duration that Mary cycled for after she caught up with Marion and when she stopped to wait for Marion
= (168 ÷ 21) - 2¹₃
= 8 - 2¹₃
= 5²₃ h

Distance Marion was from Mary when she stopped to wait
= 3 x 5²₃
= 17 km

Answer(s): 17 km