City P and City Q is 448 km apart. Justin left City P for City Q at 10.00 a.m. travelling at an average speed of 64 km/h. Carl left City P later than Justin and caught up with him at 1.00 p.m. Carl was travelling at a speed of 72 km/h.
- At what time did Carl leave City P?
- How much later did Justin arrive in City Q than Carl? Express your answer in h as a fraction or mixed number.
(a)
From 10.00 a.m. to 1.00 p.m. = 3 h
Distance that Justin covered when Carl caught up with Justin
= 3 x 64
= 192 km
Time that Carl took to travel 192 km
= 192 ÷ 72
= 2
23 h
1 h = 60 min
23 h =
23 x 60 = 40 min
2
23 h = 2 h 40 min
Time that Carl left City P:
2 h 40 min before 1.00 p.m. = 10.20 a.m.
(b)
Remaining distance that they had to cover to reach City Q
= 448 - 192
= 256 km
Duration that Carl had to travel before reaching City Q
= 256 ÷ 72
= 3
59 h
Duration that Justin had to travel before reaching City Q
= 256 ÷ 64
= 4 h
Duration that Justin took to arrive later than Carl in City Q
= 4 - 3
59=
49 h
Answer(s): (a) 10.20 a.m.; (b)
49 h
