At 9 a.m., Jack started from City M and travelled towards City N and his speed remained constant throughout. At 10 a.m., Betty started her journey from City M towards City N at an average speed of 66 km/h. Betty overtook Jack at 3 p.m. After overtaking, Betty carried on her journey at the same average speed and reached at City N at 3:30 p.m.

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

(a)
From 10 a.m. to 3 p.m. = 5 h

Distance that Betty had travelled until Betty overtook Jack
= 5 x 66
= 330 km

From 9 a.m. to 3 p.m. = 6 h

Jack's average speed
= 330 ÷ 6
= 55 km/h

(b)
From 10 a.m. to 3:30 p.m. = 5 h 30 min

1 h = 60 min
5 h 30 min = 5 ³⁰ ₆₀
 h = 5 ¹₂ h

Distance between the two cities
= 5 ¹₂ x 66
= ¹¹₂ x 66
= 363 km

Answer(s): (a) 55 km/h; (b) 363 km