The distance between Town Y and Town Z was 198 km. At 06 00, Olivia left Town Y and cycled towards Town Z. Risa left Town Y and cycled towards Town Z at 06 15. Risa's cycling speed was 4 km/h faster than Olivia. At 11 00, Risa caught up with Olivia. When Risa was 30 km from Town Z, she stopped to wait for Olivia. How far was Olivia from Risa when she stopped to wait for him?
Duration in which Risa cycled for before she caught up with Olivia
= from 06 15 to 11 00
= 4 h 45 min
= 4 ⁴⁵₆₀ h
= 4 ³₄ h

Distance that Risa cycled more than Olivia
= 4³₄ x 4
= ¹⁹₄ x 4
= 6 km

Olivia's cycling speed
= 6 x 4
= 24 km/h

Risa's cycling speed
= 24 + 4
= 28 km/h

Distance that Risa cycled before she stopped to wait for Olivia
= 198 - 30
= 168 km

Duration that Risa cycled for after she caught up with Olivia and when she stopped to wait for Olivia
= (168 ÷ 28) - 4³₄
= 6 - 4³₄
= 1¹₄ h

Distance Olivia was from Risa when she stopped to wait
= 4 x 1¹₄
= 5 km

Answer(s): 5 km