At 7 a.m., Andy started from City R and travelled towards City S and his speed remained constant throughout. At 8 a.m., Jean started her journey from City R towards City S at an average speed of 84 km/h. Jean overtook Andy at 1 p.m. After overtaking, Jean carried on her journey at the same average speed and reached at City S at 4:35 p.m.
- Find Andy's average speed in km/h.
- What is the distance between the two cities?
(a)
From 8 a.m. to 1 p.m. = 5 h
Distance that Jean had travelled until Jean overtook Andy
= 5 x 84
= 420 km
From 7 a.m. to 1 p.m. = 6 h
Andy's average speed
= 420 ÷ 6
= 70 km/h
(b)
From 8 a.m. to 4:35 p.m. = 8 h 35 min
1 h = 60 min
8 h 35 min = 8
35 60
h = 8
712 h
Distance between the two cities
= 8
712 x 84
=
10312 x 84
= 721 km
Answer(s): (a) 70 km/h; (b) 721 km