At 8 a.m., Perry started from City G and travelled towards City H and his speed remained constant throughout. At 10 a.m., Irene started her journey from City G towards City H at an average speed of 72 km/h. Irene overtook Perry at 2 p.m. After overtaking, Irene carried on her journey at the same average speed and reached at City H at 5:30 p.m.

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

(a)
From 10 a.m. to 2 p.m. = 4 h

Distance that Irene had travelled until Irene overtook Perry
= 4 x 72
= 288 km

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

Perry's average speed
= 288 ÷ 6
= 48 km/h

(b)
From 10 a.m. to 5:30 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 72
= ¹⁵₂ x 72
= 540 km

Answer(s): (a) 48 km/h; (b) 540 km