At 8 a.m., Ahmad started from City T and travelled towards City U and his speed remained constant throughout. At 9 a.m., Gem started her journey from City T towards City U at an average speed of 78 km/h. Gem overtook Ahmad at 2 p.m. After overtaking, Gem carried on her journey at the same average speed and reached at City U at 4:30 p.m.

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

(a)
From 9 a.m. to 2 p.m. = 5 h

Distance that Gem had travelled until Gem overtook Ahmad
= 5 x 78
= 390 km

From 8 a.m. to 2 p.m. = 6 h

Ahmad's average speed
= 390 ÷ 6
= 65 km/h

(b)
From 9 a.m. to 4:30 p.m. = 7 h 30 min

1 h = 60 min
7 h 30 min = 7 ³⁰ ₆₀
 h = 7 ¹₂ h

Distance between the two cities
= 7 ¹₂ x 78
= ¹⁵₂ x 78
= 585 km

Answer(s): (a) 65 km/h; (b) 585 km