At 9 a.m., Warren started from City A and travelled towards City B and his speed remained constant throughout. At 10 a.m., Irene started her journey from City A towards City B at an average speed of 68 km/h. Irene overtook Warren at 1 p.m. After overtaking, Irene carried on her journey at the same average speed and reached at City B at 5:30 p.m.

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

(a)
From 10 a.m. to 1 p.m. = 3 h

Distance that Irene had travelled until Irene overtook Warren
= 3 x 68
= 204 km

From 9 a.m. to 1 p.m. = 4 h

Warren's average speed
= 204 ÷ 4
= 51 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 68
= ¹⁵₂ x 68
= 510 km

Answer(s): (a) 51 km/h; (b) 510 km