City D and City E is 240 km apart. Sam left City D for City E at 10.00 a.m. travelling at an average speed of 60 km/h. Ian left City D later than Sam and caught up with him at 12.00 p.m. Ian was travelling at a speed of 80 km/h.
- At what time did Ian leave City D?
- How much later did Sam arrive in City E than Ian? Express your answer in h as a fraction or mixed number.
(a)
From 10.00 a.m. to 12.00 p.m. = 2 h
Distance that Sam covered when Ian caught up with Sam
= 2 x 60
= 120 km
Time that Ian took to travel 120 km
= 120 ÷ 80
= 1
12 h
1 h = 60 min
12 h =
12 x 60 = 30 min
1
12 h = 1 h 30 min
Time that Ian left City D:
1 h 30 min before 12.00 p.m. = 10.30 a.m.
(b)
Remaining distance that they had to cover to reach City E
= 240 - 120
= 120 km
Duration that Ian had to travel before reaching City E
= 120 ÷ 80
= 1
12 h
Duration that Sam had to travel before reaching City E
= 120 ÷ 60
= 2 h
Duration that Sam took to arrive later than Ian in City E
= 2 - 1
12=
12 h
Answer(s): (a) 10.30 a.m.; (b)
12 h
