The distance between Town X and Town Y was 169 km. At 08 00, Xuan left Town X and cycled towards Town Y. Tammy left Town X and cycled towards Town Y at 08 15. Tammy's cycling speed was 4 km/h faster than Xuan. At 11 00, Tammy caught up with Xuan. When Tammy was 25 km from Town Y, she stopped to wait for Xuan. How far was Xuan from Tammy when she stopped to wait for him?
Duration in which Tammy cycled for before she caught up with Xuan
= from 08 15 to 11 00
= 2 h 45 min
= 2 ⁴⁵₆₀ h
= 2 ³₄ h

Distance that Tammy cycled more than Xuan
= 2³₄ x 4
= ¹¹₄ x 4
= 8 km

Xuan's cycling speed
= 8 x 4
= 32 km/h

Tammy's cycling speed
= 32 + 4
= 36 km/h

Distance that Tammy cycled before she stopped to wait for Xuan
= 169 - 25
= 144 km

Duration that Tammy cycled for after she caught up with Xuan and when she stopped to wait for Xuan
= (144 ÷ 36) - 2³₄
= 4 - 2³₄
= 1¹₄ h

Distance Xuan was from Tammy when she stopped to wait
= 4 x 1¹₄
= 5 km

Answer(s): 5 km