At 7 a.m., Eric started from City N and travelled towards City P and his speed remained constant throughout. At 9 a.m., Tiffany started her journey from City N towards City P at an average speed of 90 km/h. Tiffany overtook Eric at 1 p.m. After overtaking, Tiffany carried on her journey at the same average speed and reached at City P at 4:40 p.m.

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

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

Distance that Tiffany had travelled until Tiffany overtook Eric
= 4 x 90
= 360 km

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

Eric's average speed
= 360 ÷ 6
= 60 km/h

(b)
From 9 a.m. to 4:40 p.m. = 7 h 40 min

1 h = 60 min
7 h 40 min = 7 ⁴⁰ ₆₀
 h = 7 ²₃ h

Distance between the two cities
= 7 ²₃ x 90
= ²³₃ x 90
= 690 km

Answer(s): (a) 60 km/h; (b) 690 km