At 7 a.m., Ivan started from City C and travelled towards City D and his speed remained constant throughout. At 8 a.m., Yen started her journey from City C towards City D at an average speed of 84 km/h. Yen overtook Ivan at 1 p.m. After overtaking, Yen carried on her journey at the same average speed and reached at City D at 1:25 p.m.

1. Find Ivan's average speed in km/h.
2. What is the distance between the two cities?

(a)
From 8 a.m. to 1 p.m. = 5 h

Distance that Yen had travelled until Yen overtook Ivan
= 5 x 84
= 420 km

From 7 a.m. to 1 p.m. = 6 h

Ivan's average speed
= 420 ÷ 6
= 70 km/h

(b)
From 8 a.m. to 1:25 p.m. = 5 h 25 min

1 h = 60 min
5 h 25 min = 5 ²⁵ ₆₀
 h = 5 ⁵₁₂ h

Distance between the two cities
= 5 ⁵₁₂ x 84
= ⁶⁵₁₂ x 84
= 455 km

Answer(s): (a) 70 km/h; (b) 455 km