At 7 a.m., Tom started from City U and travelled towards City V and his speed remained constant throughout. At 10 a.m., Barbara started her journey from City U towards City V at an average speed of 78 km/h. Barbara overtook Tom at 1 p.m. After overtaking, Barbara carried on her journey at the same average speed and reached at City V at 3:50 p.m.

1. Find Tom'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 Barbara had travelled until Barbara overtook Tom
= 3 x 78
= 234 km

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

Tom's average speed
= 234 ÷ 6
= 39 km/h

(b)
From 10 a.m. to 3:50 p.m. = 5 h 50 min

1 h = 60 min
5 h 50 min = 5 ⁵⁰ ₆₀
 h = 5 ⁵₆ h

Distance between the two cities
= 5 ⁵₆ x 78
= ³⁵₆ x 78
= 455 km

Answer(s): (a) 39 km/h; (b) 455 km